I've been reading the reviews on the 737 but haven't been able to learn if this is a fully functional FMS or an FMS "lite"  This is to help prepare for 737 training and don't need it to replicate every minor detail of the real thing but would like something close to it.  Anyone who can give me some thoughts or opinions on this FMS I'd be very grateful.

No worries on that end, Steve. Not a lite unit in that plane. SID/STAR support, fuel calcs, VNAV, Navigraph updatable. Are you concerned about a special feature?

 

The only lack on that plane is the presentation, the systems are quite solid although they won't match more current renditions in their depth. So if you would look for 737 NGs, you would get more details on the iFly or NGX, but the 737 Classic lets say benchmark still resides with the old-ish Wilco PIC Evo.