For me I'd have to review the pingback first.
I've seen too many people using those for link spam, and it's easy to do since it's an automated process. So I'd definitely want to review all pingback posts prior to blindly accepting them.
Whether they're seen as legitimate links back to you is a whole other question. You'd have to see if those were being nofollow'd (many are since they're in the comments) and a whole slew of other questions. I typically don't even concern myself with looking at those question because at the end of the day it's still exposure if the pingback post is relevant and actually worthwhile.
It's amazing how most questions, especially link building ones, become a lot easier to understand and answer if your overriding question is whether it's good and useful for real users. So forget about the search engines. If it's good for users, accept 'em. If it's not, don't.