The XTS is a pretty solid marker. They are pretty reliable and are comparible to a tippmann 98/pro-carbine in terms of consistency & efficiency.
That model that you are reffering to is a XTSE-Nemesis and was the "higher end" XTS.
Again they are older and are no longer in production, so parts can be hard to find. I personally made alot of my spare parts since the mechanics of the marker are simple. Most of the parts are similar to those of other markers, such as a Brass Eagle detent can be fitted to work on the XTS.
Honestly, IMO, they are a bit nicer than a model 98 and are fun to play with. However, $125 is a bit too high for this IMO, I think somewhere around $80-$90 is fair.
If you can get it around that price range I mentioned above, then I say go for it.
I am the most cynical person on earth.