There are some shitty people on pc, but even those people haven't been so shitty that I've wanted to turn off the chat, it's normally like 1 comment along the lines of "lol, my team sucks". I imagine the game will have some long legs before the community becomes toxic, especially if Blizzard keeps new content coming at a regular rate.
In my ~8 hours of Overwatch, the chat has been pretty decent. Aside from one salty guy who kept insisting everyone report Bastion players, it's mostly 'gg wp'