I've been using UserEcho for a while now and I'm so happy with it. I can't say enough positive things about the people who run the company and serve their customers. I've never felt so valued as a customer before - they are immediate to respond and help me reach my goal - making custom hacks/adjustments to my website free of charge. It's incredible. They should really charge more - it's a steal the value we're getting right now.
Powerful search feature let's customers/users find the info they need
UserEcho is very inexpensive ($15/mo per admin)
Customer service provided is second to NONE
User voting system is awesome
Design layout builder is a little clunky, but not too bad