HN gave me a wide variety of feedback, some of it really excellent. Try posting a "Ask HN: Please review my startup vivekjishtu.com" or whatever.
Launchly is awesome but doesn't have a lot of eyes yet. Do post there, though, you'll get some great feedback.
Usefultools gave me a tiny little bit of a review, but mostly just regurgitated my copy. They yielded a good bit of traffic, though.
My best review thus far was from a random blogger who had reviewed a competitor. I sent him a personal email saying "Hi, I'm impressed with your candor and feedback, would you please review my site? Here's a promotional premium account."
Also, hang around Launchly or HN for a while (I see you just signed up for HN) and give other people feedback. Both have reputation systems. You might even have luck giving other people serious feedback and tacking onto the bottom "if you have a moment to spare, could you give me some feedback on three-year-project.com"
However, in terms of long-term recurring members, I can't say any of those paths have yielded much. This might be more a reflection of my service than the nature of the promotional channels, however.