Only about 5 of my recent 15 orders actually left a review for me. It doesn't have to have text, just a star rating works. Then again a lot of my orders are from full-fledged businesses handling orders left and right.
But if you have the time and are able to, a review is appreciated. It's nice to show vendors that you mean business!
+1. Buyer rep is important. Shows venders that buyers aren't out to get them, we just want some good shit.