Yeah its been no problem at all. It makes a very little amount of noise in 4th gear but nothing that would make me take it off. I prefer the gear spread of the Shimano cassette vs the SRAM, so this is the best of both worlds. I can't notice any difference in shifting performance to having all SRAM parts.
No I don't notice anything negative with them. I do ride the bike park quite a bit and prefer the stability. I feel very confident when riding this bike.