I purchased a copy of MS flightsim 2004 as well as CH products pedals and yoke after I started learning to fly hoping that it would give me some extra practice. To be honest I have found it of limited use – you definitely do not get the feeling of realism you do in a real plane. Practicing a stall for example in the sim – you do not get any of the cues you do in the real world. But having said that I have found it helpful to practice the different steps for doing some of the maneuvers.
Also these simulators could be of more use to those training for an instrument rating – you can practice your instruments scan, recover from unusual attitudes and practice landings with ILS. There is another product called Elite – they sell software and also sim hardware and the hardware is actually an FAA approved sim (although I believe for instrument only). They have one at our club and although I’ve never used it I have tried the hardware and it does feel realistic. Apparently for the FAA private rating you can take the required instrument time on this sim although so far I’ve done it on the plane under the hood.
I downloaded the Elite software and to be honest it looks and feels worse than the MS sim IMHO.