Unfortunately all parties have a lot of crappy councillors, because so few people care about local politics.

That said (and this is honestly my experience, not just partisanship) while I'm sure we have our fair share of bad ones, I honestly think that we do better in this regard than the other two parties, precisely because our strategy for decades has been to get councillors first, let people see we can be trusted in local government, and then try to get MPs in regions where we've got councillors. That strategy wouldn't have been as successful as it has been, had our councillors been that bad.

(Of course if we have bad councillors in your area, the obvious solution is to stand yourself!)