My service has been fine before and after the update (Verizon in so cal). It actually got a lil better with the update I think. It really depends on your area and where you are located...
Still waiting on 5.1.1 though and no news about it has surfaced for us big red users
Can't say that I've noticed any signal issues, but I'll say my battery life has been a bit more inconsistent since the last update with restarts needed more frequently to keep it in check. I'm probably due for a full reset, but trying to hold off until the 5.1.1 update before going through all that.