A lot of vouches usually means they are more trusted, but it's more like a combo of vouches/post count that helps me feel better.
Like someone mentioned before, it also is for the quality of the vouches more than the quantity. I'd definitely feel that I could trust somebody more if they had only 10-15 vouches that involved with pin/account trades/sales, mming, etc. than someone who has 500 vouches that all came from getting 1-30 mining for people(for free usually, at that).