It's pretty good.
I'm playing on PS4, because I am a heretic.
It reminds me a lot of Team Fortress 2, although rather than nine distinctive characters there's over 21.
It's interesting that despite having such a large cast, each character is still very distinctive and unique in terms of weapons/gimmicks and roles within the team.
The game is certainly geared toward competitive MOBA-like action, which is the only thing that's put me off a little, since I've never been interesting in taking games that seriously... what with precise team coordination, communication and correct class selection. I just want to shoot.
It's very good. If anyone's in high-octane-objective-focussed-shooters, you should try it out (when it's on sale).
(https://metrouk2.files.wordpress.com/2016/05/overwatch-gif.gif?w=620&h=348&crop=1)