My feelings towards self inserts can be split into two.
1. If the self insert feels like a natural part of the world without it being thrown into someone's face then it shouldn't be to bad, they are a living breathing part of the world without much of a problem. They could just be working a job...
Honestly depends on the fandom? If the fandom has some good people with good knowledge of the content then it isn't too bad! If people are insufferable? Then it's a bit hard to get into.