Have run both(well at TC6) & a T3'12.
Box set-up I prefer the Xray, easier to drive, it rolls better and has a more neutral feeling.
I have gone faster with the xray than the TC6, I however did not give the Tc6 enough chassis tuning to get it perfect, my track is swamped with xrays & I got a good set up from a local driver that is working for me.
Like stated above associated parts are cheaper but more fragile, in the end they cost the same to upkeep, I always break on pratice night with the associated.