Hi Norma,
Couldn't tell you--we haven't used it and I don't know first hand of anyone who has (their website suggests it ought to be easy to find users for feedback). Their website does look good and their program feature list appears attractive. It reminds me a bit of SPSS's break into the online survey market from 2000 or so (see http://spss.com/software/data-collection/). How do these kind of programs differ from MediaLab? Not having used Qualtrics, I can't really say except that we don't really see MediaLab as a "survey" program so it's not really apples to apples, e.g., see:
http://www.empirisoft.com/Support/showthread.php?t=17
Hope that helps,
Blair