XTR FD was the best upgrade I have made...
I replaced my FD (LX) with an XTR (952??) a couple of years ago, and it was the best drive train upgrade that I have made on my bike. At the time, I read the reviews on MTBR.com, and they pointed out that the XTR FD had some unique capabilities that were not available in the lower lines. Having said this though, with the typical trickle down effect, the newer XT may have the same features as the the older model that I purchased (its been long enough that I forget the specifics).
I would check out recent reviews on the XT & XTR FD's, paying attention to the model numbers, to see if there are still any differences other than weight & bling-factor. :thumbsup: