Well it certainly won't hurt. I read a blog declaring "any review is a good review," and while I believe this to be true and it may help to influence them clicking that "sale" button I don't think its really helping bring new people to my books. At least not dramatically.
Perhaps my reviews are still too few to truly influence people looking for them by review, but they still make me happy. When they are reviewed off the sale's sites they tend to get a few new looks for about 48 hours.
But despite the fact that they seem to be limited in their helping, they are still thrilling and encourage me in my writing. They make me want to write and cover and explore new situations. Its also very encouraging that my reviews tend toward more stars. In fact, I have only one rated at 2 stars. It makes me pleased to be a writer.