It probably depends on the comps, obviously… But, honestly, at 6 seconds, he probably is more reliable than Ashe and I cannot believe I am saying that. I would need to test to confirm, but the 120 into shots will actually get kills whereas dynamite is mostly for Ult. It is kind of hard to combo off it with all the damage mitigation in the game.
I also kind of prefer 76 against dive because his sprint will get you away a bit more reliably than the coach gun.
The only real issue is that his ultimate is still the worst in the game and Bob is a free tank. So… I do not know. I feel Soldier probably beats her in the MU at least, though. Ashe is probably better for general purposes or if you have a Mercy who likes dps.