I'd have to say the Engineer is my top pick, especially since I prefer either setting up Dispensers for my team or turrets, and I love control point and defending the main room with my wrangler.
After that it'd be spy, since I can stealth my way around enemies and catch them off guard. My personal favorite strategy is to go spy, turn into an enemy, say "spy" every so often, and get them nervous and on edge to make it easier for my team to kill them.
Demoman and Sniper would come next, they're my "when all else fails" classes.
Heavy is okay, but not fantastic for me. Too slow, makes me nervous of backstabs. I can never seem to play the soldier right. I'm a bad scout, and I'm no good with the pyro's short range flamethrower.
After that it'd be spy, since I can stealth my way around enemies and catch them off guard. My personal favorite strategy is to go spy, turn into an enemy, say "spy" every so often, and get them nervous and on edge to make it easier for my team to kill them.
Demoman and Sniper would come next, they're my "when all else fails" classes.
Heavy is okay, but not fantastic for me. Too slow, makes me nervous of backstabs. I can never seem to play the soldier right. I'm a bad scout, and I'm no good with the pyro's short range flamethrower.