Yeah by far my most played hero is McCree so I guess I do have some experience with him.
His ult isn't as strong as it first looks. You're a huge, slow, glowing target when you're ulting and if the enemy widow isn't playing literally without hands, you're guaranteed a bullet to the face when ulting. If the enemy has a Genji you're better off forgetting that you have a Q button. McCree can pull off his ult in two cases:
a) area denial from behind Reinhardt shield
b) surprise buttsex if you get a good flank off, which is weird because McCree is not a flanker, so it's silly that his ult kinda requires flanking
Other than that the hero is complete bullshit. Again, I say that as a player with most hours on McCree and I actually really like the character, and not just because of it's obvious strengths. The fact that it's double picked in pro games only proves my point. He deserves a nerf asap, closely followed by a Widowmaker nerf. The biggest problem is that any kid can pick him up and spam right click for massive damage, his skill floor is very high and I hope that whatever adjustments they make to the hero lowers the skill floor but keeps the skill ceiling or even raises it.