We currently use Rapid PHP 2010 at my work. I downloaded the Rapid PHP 2011 demo to evaluate whether or not it would be worth it to upgrade.
However the first time I ran the demo version after installing it, it said I only had 14 uses left. (And then it immediately had to restart, so that cut me down to 13)
I think this may because I also used the 2010 evaluation before we upgraded to it last year. So maybe it's sharing evaluation counts or something.