That's a great offer, too bad it expired.
I tried Prodrenalin and was under whelmed with the possibilities. No stabilisation, no picture in picture, no sound editing.
However, today you can get PowerDirector 12LE for free. I use that one mainly because it came free with my Dell XPS and I like it! I wished I could install it on my notebook as well but it was a one machine license. But now I have a second one for free!
It is much faster in rendering than anything else I tried (including Prodrenalin, Gopro Studio, Imovie), and it has some features many other products lack. Like picture in picture (nice FPV screen overlays) and stabilisation and soundtrack/narrator adding. Also movie templates like Gopro Studio.
There are quite a few options that nag you to upgrade to the full package (which is less than 60$ and quite a steal) when you click them. But still, with what is left in the free version you have a lot of possibilities to produce a good clip or complete movie.
Like many good video editors it's only available for Windows I'm afraid.