+1 on the V-Studio - Horrible to work with and setup - but once locked in - the most reliable solution for live backing tracks I know of.
Also having each of the songs on their own individual buttons is a huge advantage - you can change the set at whim and no problem.
and finally physically S.O.L.I.D.
Its the Hummer of backing track setups - I've used one unit for 10 years in hideous conditions - failed - twice (as in needed reboot) I would say over 1000 shows in that time.