I used FS2000 when I was doing my IR to help learn the local procedures, and found it helped quite a lot. You have to try to be fairly disciplined in terms of identifying all beacons and such like.
It's absolutely nothing like flying, so using it to practice aircraft handling is pointless, but you fly can IFR procedures from the actual plates, so it's as real as you want it to be.
The beacons all seem to be in the right places, but some of the morse idents are wrong, but that's good practice too.