I tend to be in the same boat, but I feel there's an important caveat: the person providing the criticism needs to be reachable if the criticism itself lacks substance. A complaint just for the sake of venting does no good.

Take, for example, a recent review on my iPad app:

    As a creative professional I can tell you that this is junk. Today I had an important meeting and this app acted up to the point the client laughed hard for how bad it was. Stay away!

There is nothing specific in there that I can use to improve the experience. Not one user in thousands of daily active users on this version has reported anything I could possibly assume might be what the reviewer is talking about. Further, because it's on the iOS App Store, it's impossible for me to reach the person.