I think they are good for fittings to compare clubs and maybe balls, but otherwise I tend to ignore them. I do have a PRGR swing speed monitor I will use at home in the winter in preparation for a golf trip. I don't know how truly accurate it is, but when I make a better swing the # is higher so I use it to try to get my swing going mid-winter.
We have a 2-tier covered heated range about 30 minutes away that I will sometimes visit in the winter. I've learned to ignore the Trackman there. It seems to work ok if you are able to get a stall in the center, but most times you wind up way down one end or the other. If you are way down the left end of the range (generally where the open stalls are) and hit towards the left targets then the Trackman may not pick up your shot (it took me several visits there to realize this d'oh!) Apparently it's aligned to the center targets, but those are hard to aim at because the range is not in an arc to more easily allow to hitting to the center. If you're a right hander on the left side of the range you need to hit a slice to get at a center target....which is generally the shot we're trying NOT to hit.
