All these guys have it right on the money. G2 is without a dought the best learning tool for all types of flying that you may encounter and that means 3d flying as well. With the right amount of practice you will find that your realtime flying will not only become more precise, but you will become much more confident and in control of your planes.
The stock DP Ultimate does not feel anything like the real one because its setup to be a .40 size plane but you can always download a few from different sites where people have set it up as a 1.20 size model .
I spent a good part of the year 2001 flying the sim and practicing 3d maneuvers because i didn't have a plane to fly ( was saving up for an avistar) when i finally bought an avistar, i outgrew it in over a month.
I flew many planes between then and know, but i just finished building my H9 Edge 540 with a ZDZ 40b and on the third flight i had it doing torque rolls and harriers. It was actually easier than the sims Edge (Add on 4)