I had a great time during the beta. I was expecting this game to bomb but I was really surprised at how much fun I had. The only thing I really hated in the game was Mcree's flashbang/fan combo, even the ultimates didn't bother me. Widowmaker is head and shoulders above the rest in terms of effectiveness.
My biggest issue is with the game's horrendous movement. Aim really matters in the game, which I appreciate a lot, but because everyone moves slowly and predictably, the skill cap for aiming is way way way lower than it is in a game like TF2. I feel that if they could somehow resolve this one area, the game would be amazing. Idk how they'd do that though. It'd take some core reworks to introduce advanced movement to the game. If they ever did that though, it would seriously bolster the FPS side of the game, and even go a long way in balancing a character like Widowmaker.
I gotta say though, going back to TF2 after the beta sorta feels like returning to an abuser. Playing a polished, balanced, optimized, and populated game like Overwatch only further underscored how hilariously neglected TF2 has been as anything other than a hat simulator. It makes me sad :(
I'll definitely be buying Overwatch and I expect to put at least a couple hundred hours into it, but since Blizzard has a history of fucking over their dedicated players in favor of mass appeal, I'm sure it's only a matter of time until they do something that makes me quit like they have 3 of their other games