The upgrade gives you a fancier keyboard, but I find I can navigate easily using the free version, and have no trouble opening and closing programs, etc.
I'm using it to control my Mac mini - haven't had the desktop up on my flatscreen since I installed this app.
BTW - there are a number of interesting remote app's for those running WinAmp, Linux, Myth TV, etc on the iTunes AppStore.
Just go to the AppStore, search for "remote" and select "View All"