I like Trymyui because as a tester, I have had Great results. If my demographic meets the test requirements then I get to take the test. I check every day multiple Times a day to see if there are any tests available. The only thing I don't like is, I don't personally get tests. These tests are available for anyone in the same demographic so we kind of have to fight over who clicks on the test first.
I have never had a problem with this company paying me within 3 days of taking a test. I answer honestly and have nothing but 5 stars on my profile. If I know about any other sites that I could also make money from like this one I would definitely join.
I have no idea how trymyui finds the companies that ask for testers.
I do, however, wish there were more tests. Multiple Times Per day, I actually like doing them.