welll... i was also comparing these markers, and i decided on the tlx. but thats me. at x paitball, the xtra is 74.77 i think and the tlx is 86.77. they pretty much have the same features. . dual trigger frame , semi auto, anti double feed drop forward and vertical drop. they both only come in blue, the xtra lighter blue tha the tlx. the tlx has an aluminium trigger so that is better. close up i personally think the tlx looks better, but from 20 yards nobody would be able to tell the diff. the tlx has been reviewed to preform better, but not necessarily by a lot. most ppl say they preform the same because they are mechs, but that is really up to u. if ui think thye are the same, get the xtra, if not, spring hte 12 bucks for the tlx cuz it is lighter i think, and the co2 bottom line is steel braided.
the info and pic for the tlx is
http://www.xpaintball.com/spydertlx.html
thie info and pic for the xtra is
http://www.xpaintball.com/bluspydxtrap.html
hope this helps, i worked a little bit for this one
(rep point?)