Years ago the sim helped my overcome a HUGE problem I had. I just couldn't fly anywhere near the ground. I rarely got below 75ft or so. I used the sim to practice flying low to the ground. Now I rarely fly ABOVE 75ft!!!! But I owe it all to the simulator. I made me feel comfortable flying that close to the ground!!

As far as which sim? I fly Realflight G2. It doesn't have all the bells and whistles of G3 or AFPD but it does a pretty good job IMHO. That partially comes from the fact that I refuse to own G3, even if it was given to me!!!!!!! But that's another story. If you come across a copy of G2 on Ebay or in the marketplace it might be well worth it to pick up at a lower price, it will definitely help improve your flying skills

Hope this helps

Ken