Looks like I'm finally appreciating Overwatch now. I have past the frustration wall - now that I have basic notions of who counters who, and that I have a couple of mains, I'm starting to really have fun in the game.
In TF2 usually I don't play more than 1 hour. Play a few maps, have some fun, and then that's it. But in Overwatch there is something that keeps me playing;
I think it might be that the characters are a lot more dynamic in Overwatch. For example, Diva can thrust in, wipe some guys, then retreat using her shield.. Or if she has her ulti, she can thrust in and activate it to launch a real bomb to explode, and then get a new mech right away.
And it's kind of the same with all the classes. You can do crazy stuff with all (or almost all) of them. And the weapons feel way more badass than in TF2 - you really have the feeling to be OP if you pick the right class.
I just wish more people were playing Support. I'm kind of tired to play Support during half of my games, because no one is willing to
(but in TF2 it's the same thing. The number of games I ended Medic because no one was Medic is quite high)
So far my favourites are Mei, Torbjorn, Mercy, Zenyatta and Lucio. I also play Soldier, Reinhardt, Pharah, Diva, Roadhog or Hanzo depending on the situation.
I would really like to main Symmetra but she is very hard to play, and I feel useless most of the time I play her (her teleport alone is not worth it to take her imo. It's not like TF2 where there are ~15 team members - here there's just 5 team mates, so your teleports are hardly used)