PG81s are not terrible at all. They sound pretty much in line with how much they cost. That said, they are grainier and not as "pingy" as SM81s. I love me some SM81s, though.

The Shure PG series in general is widely hated because of it's budget status.... I did find the PG56 tom mics and the PG52 kick mic to be decent. Not great, but decent. The PG57 is a piece of **** though. I would say the only PG series mic I wouldn't mind owning is the PG81.