If you are interested in a serious sim for honing your 3D skills AFPD is the way to go. G3 is a nice sim but its really no comparison to Aero Fly Pro Deluxe. Plus is has trainers, jets, foamies all sorts of scale planes old and new. IT also has 3D and scale helis that fly like the real thing. I have a lot of fun with the GEE BEE, its a booger to try to land...
There are tons of planes and scenery you can download as well. Also, if you dont like the way the plane flies you can play with the planes physical characteristics and it will respond just as a real plane would to the changes. The only thing I have read is that people say that AFPDs planes are harder to snap than a real plane. I played with the P51 and now it is just a snappy and tricky to land as the real plane. ALso, you can use your own transmitter with AFPD and setup planes exactly like you would your real ones mixes and all.. Just remove the TX module and go for it.

Im speaking from experience when I say that if you want to improve you training, areobatic and 3D skills,, and are willing to put the time in ont he sim AFPD will make you a much MUCH improved pilot.

Mike