[url= http://www.chainreactioncycles.com/Models.aspx?ModelID=1594 ]these[/url],
[url= http://www.chainreactioncycles.com/Models.aspx?ModelID=1597 ]and these[/url]:
The supposed level of sealing. XTR inner cables are also Teflon coated, I think XT ones are just regular inners
As far as normal people like us are concerned?
Just the price.
The XT outer cable is sp40 (which is the old XTR)std end caps, and stainless inner cables.
The XTR is the new sp41 (basically the same) outer but with sealed end caps and the inner cable is smoothed out and fluorine coated for a lighter action.
IMO XT spec is all the cable you'll ever need for trail riding.
If you're racing and have XTR groupsets, then the XTR cable gives more precise lighter shifting, but needs more attention to keep it working perfectly.
Think race car gearbox and sports car gearbox. The service intervals are much longer on the production version. The same principle applies here.