Hey Monkey... I'm pretty much a noob but have many hours on Realflight and FMS before I started flying for real and can say that FMS is not very realistic... Basically its good to teach control reversal and little else.

Realflight and others are much better at simulating actual flight with wind and much more realistic flight... I mean even basic things FMS doesnt have like banking and then holding up elevator to turn maintaining altitude... but more... some things seem weird with more advanced aerobatics but I guess there really is no 100% substitute.

I feel the commercial sim was well worth the money even though it is overpriced but I must say sitting in a recliner in my underwear in my study flying realflight is not nerve-wracking like getting in a precarious situation in real life! Just remember that! (not the underwear part... the being outside with real plane is just harder part! hahah)