I played medic for a long time, but switched to scout recently.

I really enjoyed medic. Being in the proper position and playing smart consistently is very difficult and my favorite part about playing medic. When you are on the right team, doing the right thing, you feel like you are the part of a well oiled machine which relentlessly provides your team with solid advantages. On the flip-side, it's easy to make a few mistakes and feel as though you've entirely failed your team.

Scout is a lot different for me. I've turned it into a minigame of sorts: try to hit every shot. That's it. It's a very linear progression, starting out hitting nothing then trying to hit everything.

And scout movement is like medic movement on steroids. I can have a huge presence just by movement tanking -- and it's easier to hold S on scout than it is on medic :)

I mained medic for a long time in pubs and low level highlander because honestly, TF2 was my first shooter and I couldn't aim any gun in the game apart from the healing gun when I started. For a while I kind of enjoyed it, but I started hating medic pretty quickly - I didn't like being entirely dependent on the team to get anything done.

Pyro was kind of an accident. My best friend was a really good pyro at the time and taught me how stuff works and I just got sucked in. At this point I've buried almost 700 hours in the old fire guy and I still get all giddy when I get reflects. It's not a very skilful class but there's a lot of subtle things about it that most people don't realize are crucial, making the difference between a pyro that just stands there spychecking and one that truly helps his team with whatever is needed.

I'm trying to get better at other classes and dwell into sixes a bit but I think I'm a pyro main for life, sorry to say :O