If you plan on live use and actually putting it on the floor and(gasp)stepping on the device you purchase,then yes the GT-8 is the way to go.Line 6 has decent amp models,but its just not suited for actual gig work as the GT-8.The XTL is a good 'concept' but its not flexible enough.The GT-8 rips with massive distortion.With mic placment,cab/amp choices(designed to sound good 'live'),effect chain manipulation e.c.t. the XTL is just outclassed.

Even if you wanted something to record with,I still wouldn't recommend the XTL.An XT pro would do awsome if you had the money and the regular XT is fine for recording and is a $100 cheaper.