I have had Realflight G3 for over a year and have enjoyed most of the free patches/updates they have done. The problem is that awhile back they made some major changes to the flight model and ground handling, and things have not been the same since. I don't think it's realistic to be able to knife edge and drag a wing tip on the ground at 75 mph in a 40% plane and recover with no problem. In real life, of course, just skimming that wing tip a little bit on the ground would cause the whole plane to auger in. Also, like someone pointed out, there are no realistic snap tendencies. Just try using elevator and rudder only to do snap rolls or spins, and you'll find that G3 (or G3.5) simply doesn't have realistic snapping. You can mimick a snap or spin by adding in ailerons, but you shouldn't have to.
There ARE a lot of free planes to download for G3, just check
www.knifeedge.com and go to the forums, then the swap pages. There have to be over a hundred now, and the folks that are making them are doing excellent work.
I'm thinking about selling G3 and trying out AFPD or FS-One. I NEED to have realistic snaps to practice high alpha flying realistically...