I've been using Blurbpoint for a while now and liked them. They were's "amazing" but they did a good job...3 stars sounds about right to me. I have a tiny limited budget to work with and I had to put them on hold or cancel since I decided to use the budget elsewhere, part of which is here at SEOMoz. They worked on 5 keywords for me and I increased rankings well, not overnight, but over time.
