The XLT was my first machine that introduced me to the world of metal detecting. Nothing like jumping into the deep end of the pool, especially not knowing any thing at all about metal detecting back in 1999. Regardless once I learned it, the XLT found me some nice things.
You'll always have the secondary market when it comes to detectors so you can always find on long after White's stops producing them. I found myself two great discontinued machines used, the 5900 Di Pro SL (no longer have.), and the XL Pro (never getting rid of.). So XLT's will still be around for a good long time to come.
I like my V3i and MXT as the two primary detectors and the XL Pro gets used from time to time as well. With those three detectors I believe I have the spectrum covered from a frequency standpoint. Some crazy fellow even tried to talk me into a TDI a while back but that detector would have never been used by me.
However, if I ever get the itch to go prospecting, I'd consider the TDI over the GMT only because the TDI would seem to me to be a better fit for prospecting and other detecting aspects where I believe the GMT is more of a unitasker when it comes to detecting.
Bottom line, yes that is a great price for an XLT and if I was in the market, it would be money well spent on a quality detector.