I was actually looking at one of the more recent models the other day.....took it for a spin, forgot who good they were.......
The (non-vista) Jag-Master though, is really nothing more than a Jazzmaster Chassis with a Strat Trem and basic twin Humbucker electronics.
I had a few probs keeping it in tune using the trem, mostly because the strings were new and had not stretched out yet, it was a little more "tamed" after I played it for about 20 minutes.
The sound overall is more of a vintage deal, the humbuckers must be around 8.4K ohms or so, it's got a bit of the Van-Haleney mid-power humbucker gain thing going on (midrangey). it's a pretty good all around guitar, though the tuners feel a little "chintzy" if I rememebr right.