Wow, I have had completely the opposite experience, literally never had a bad driver with Lyft (and my travel patterns take me to different locations, I'm not just in the same two cities over and over again).
TBH, I haven't had many bad uber drivers either, but the ones that are bad seem to exclusively be on the uber side. I think it's because most newbs start off with uber and only later branch out to use lyft as well.