Neat! Glad this thread existed - I just randomly stumbled into them today (I forget from where - one of the handful of sites that may have sent me an invite to a higher-paying focus group type study), then at the end of the survey, unusually for a third-party-hosted pre-survey like that, it asked if I wanted to join the site, and I was like... huh, I guess so? Figured I should check here first to make sure they were legit. Sounds like they are, so I'm gonna try them out now!