Furry Art Pile

Explanation :

Usefulness : This is my opinion, on a one to ten scale. It covers how practically you can defend yourself against an enemy or attack him dead. If a character has high usefulness, that generally means he is, well, very useful and is easier or more practical to use.
Skill Level : This is the "It takes this level of skill to use this class well" kind of bar. Basically, if I say dumbass, even a dumbass can use this class.

Scout.
Runs twice as fast, captures twice as fast, and is overall a great class. Piss weak though. Biggest enemies are sentries LV 2 and above and pyros. Plus shotguns in the face, but that's a given.
Usefulness : 8. Reason : Dart circles around opponents as you shotgun them stupid. If you know how to dodge well, this is GOLD.
Skill Level : Mediocre. Any idiot can PLAY a scout, but any half competent player will not die if and when he bumps into the first enemy (Unless it's a pyro or a demoman or soldier. They pretty much one shot kill the scout)
My usage : Quite often

Soldier.
Well, the guy is slow as hell, but he does a good amount of damage. I like rocketing corners where I think there are snipers. I got many a kills from splash damage. They are also useful for rocketing past a sentry's sight. Rockets don't have range limits like sentires do *HINT HINT* (Read : Don't run into sentires you idiots).
Usefulness : 10 . Why? You can rocket jump up high places, cause massive splash damage to campers and maybe kill a whole GROUP of people. The rocket also has no range so it will travel until it hits something, and when it criticals, it criticals HARD, dealing 2-3X more damage on TWICE the splash area. MASSIVE.
SL : Dumbass. Yes, even a total dumbass can USE the soldier. Aim and fire. But. You have to be a pro to be good. Pros know the rocket is slow and try to calculate where the enemy will be when it hits, and pros jump up high places a lot to confuse enemies.
My useage : DAMN often.
Special Note : People who say "Soldiers are noobs" are complete idiots. Addendum : People who say soldiers suck and instead praise the cheap-ass spy are retarded, with a certificate.

Pyro.
Eh, hit and miss. To be honest, this guy is annoying if the enemies pile up and you run in and ignite them. The flames don't deal much damage but cause consistant burning for about ten seconds. The two are seperate damages so if you keep your FLAME on a BURNING enemy, it does a good amount of damage. Except the range is ridicilously short and you will likely never really crawl behind someone to use it. Even then they can run away, pick up health and or get medic heal'd , so while it's useful in group-raping, there are precious few chances to get to enjoy it.
Usefulness : 4 . Water kills fire, medic kills fire, health kills fire. Practically useless outside of corridors and doorways.
SL : Mediocre. The pyro is fragile and tends to die from 2-3 shotgun blasts to the face, which is where he has to be in order to light stuff on fire.
My usage : Strangely?Often.

Demoman.
You know, I'm usually smart enough to know which class to use, since I tend to focus on usefulness and power. And yet, I dislike the demoman. For some reason, the arc of his normal #1 gun's shots just annoy me, I can't quite place a shot where I want to, which is insanely rare. They arc lower than they should. Point being, the demoman's #1 gun fires on-impact bombs that explode, dealing ....well *shrugs* bad-ish damage. They bounce around corners and in places, making them extra useful for clearing out sniper nests and pesky turrets. Gun #2 fires detonatable sticky bombs. You can deploy 8 in a pack before you need to reload, and they can be detonated whenever you press the right mouse button. Their usefulness is hindered by the fact that the enemy can see your bombs.
Usefulness : 10 . Lob bombs around corners to avoid damage, blow sentries and stuff up, or plans traps in the form of sticky bombs. Pure sex.
SL : Pro. I'm sorry, but only the really good players will truly be able to use this guy. The range of his guns is terrible, so he has to be close-ish to do anything cool, and the damage of 1 bomb sucks.
My usage : F*cking rarely.

Heavy.
DAMN. Fucking pure gold. Okay, so he has a TON of health, the highest in the game. Okay, he moves slowly. But give him a narrow corridor and he will fucking rock your world. ESPECIALLY if atleast 1 medic heals him. 2 for hilarity points. You see, the heavy is the only unit in the game that can fire massively strong, constantl pain around. He is incredibly inaccurate over distances more than a demoman bomb, but his shots still hurt like hell. Although he is also as masive target, and spies usually go for them first for obvious reasons, playing as a heavy is discouraged on big open areas (HI SNIPERZ).
Usefulness : He kills, and that's it. So in terms of usefulness, 2. That's because he's a huge, slow target that really, REALLY kills.
Usage : Mediocre.

Engineer.
Okay. this guy is piss weak. Attack, hp - all weak. However.
He has the strong STRONG advantage of being able to place teleports on the map, a dispenser that slowly recharges the health of anyone nearby - not to mention more metal for him to build stuff with, AND ammo for everyone - , but it can also build a nifty little sentry gun. Plant them in hard to attack places with a lot of coverage and watch the enemy wriggle....until they figure out they need to use a damn spy. (Did I mention spies suck?) Basically, they are insanely important to any battle effort.
Usefulness : 10+++. Plant a teleporter entrance at your base, and an exit near theirs. WOOSH. Travel time per transported unit down by 90%. Dispensers to heal people and re-stock ammo in annoying, no-ammo places, and sentries to protect critical areas.
SL : Sort of above average. Placement and tactics come into play as an engineer as you need to measure where to put stuff and which areas to cover. It gets annoying sometimes when you are in a hurry >.>...
Notes : Try setting up a whole sentry wall. 2-3-4 engies covering eachother or major entry points with a pyro or 2 constant spychecking. This strategy is GOLDEN for defending control points. Fully upgraded, those 3 turrets will shred anything they don't like - and fast.
My usage : Almost always (highest atm at 4 hours something playtime)

Sniper.
Sorry, snipers are gay. I like them but they are still cheap.
Camp, wait an hour, then press a button. Cheap as hell way of getting kills. Due to how small most of the maps are, not only is using a sniper hard/impossible, it's also not worth it, as you are fully exposed when you snipe, so there is a good chance you will get a rocket in the face trying. Not BAD, just...gay...cheap.
Usefulness : Oh look at me, I shoot stuff from miles away. Too bad there's maybe ONE or two custom map in the game that won't make the enemies knife you to death >-<. 3.
SL : Nothing. A brain-damaged retarded hick from an inbred family of armadilloes can use this guy. Camp, press right mouse, press left, get kill. ZZZZZZZZ ....
Usage : Rarely, when certain sentries annoy me and I can shoot them but they can't quite get to me.

Medic.
Arguably the most important unit for the sole reason that he keeps everyone ELSE alive.
The guy is mediocre in most aspects. His health is okay, his ranged weapon is a syringe gun that...is weird (HAven't used medic a lot). But he can charge up from healing others and unleash one of 2 kinds of ubercharges currently avaialble. The first and stock-option ubercharge is a ten second invincibility timer. Needless to say, take a scout, get near a control point and use it.POW, game won. Type B is, instead of ten seconds of INVINCIBILITY, you get a 100% CRITICAL RATIO. Meaning every single shot you land will deal MASSIVE fucking damage. This is most useful on pyroes, soldiers, and heavies.
Usefulness : 15. I'm sorry for being gay and breaking my own limit, but hey....
SL : Low. Point and heal, following people around. Not that hard, but still not cheap, as dodging and healing people usually takes skill (IE not staying in the door way people are sniping from to heal someone).
Usage : Almost never (Will change soon)

Sniper.
Okay, I will be frank.
I think the spy is fucking cheap. Very useless, too. And here is why.
Spies. Suck. You disguise yourself, cloak, and uncloak where nobody can see you. Yay, you sneak up behind someone and you have a cheap way of killing ONE person. Because then the rest rape you up the ass harder than anything ever before. You can also cheap-shot sentires and teleports with this, but, come on. It's faglicious when you have a wonderful defense going, someone just wanders in and blows your stuff up I KNOW it's supposed to do that, but COME ON, THAT IS CHEAP AND JUST RETARDED.
Usefulness : I hate this bastard, but cloaking and taking out start-point sentries is, sadly, useful as hell. 8 . HATE this guy.
Usage : Rarely, although more than the medic.
SPECIAL NOTES :

Reckognizing diffirent kinds of spies.

HEAVY spy : Will run FASTER than a "normal" heavy would run, obviously.
SCOUT spy : Will run SLOWER than a "normal" scout would run. These are hilariously easy to kill, too.
MEDIC spy : If you shout "MEDIC!" near one and he doesn't try healing you, you know you have a spy on your hands. Keep an eye on him and if he tries sneaking around and or not healing anyone, slit his throat. Not that common but easy to find.
ENGINEER spy : Too easy. They run in from your main entrances usually and camp near items like sentries until people leave so he can sap them. Spy check engies near gears to avoid this. Engie spies also have the SHOTGUN out. Engineers most often naturally move with their wrench to flash-heal their gear or upgrade them. I'm one of the few who put stuff up and run around in the area killing stuff. Works like a charm.
SNIPER spy : Obviously, snipers need a lot of range. The machine gun is piss weak, therefore useless. If you encounter a sniper in a weird part of your base, especially in or near corridors, don't be afraid to slit his throat or shoot him in the face, it's most likely a spy.
SOLDIER spy : You know your soldier is a spy when he isn't barraging rockets at the enemy. This is less obvious, but do try to keep an eye out.

Self-notes : Will begin playing a LOT more as a medic soon, I want those damn achievements Xd...Over.