That $25 offer has been there before and will be there when you are ready.
So what makes a G3 lover love G3 and a AFPD lover love AFPD?
Because they own them!
It's a lot like doctors. If you ever mention to someone that you need a doctor they will always recommend their doctor, why, because they convince themselves that they have the best doctor otherwise they'd be stupid for going to that doctor. Someone has spent the money on a sim and they own it therefore it must be the best, otherwise they made a bad choice. Of the few that have owned both there aren't a lot of reasons to prefer one over another and of the ones who have a preference for one it is pretty evenly split between the two sims.
Either way you'll be a better pilot for practicing on a sim but untill you get that computer it is a moot point.