um.... "industry standard" comes to mind; it is what "the big boys use".... i have had both at the same time, and the tritons sounds do not impress me in the least. the effects are subpar in my opinion, and the soundset is third rate (behind the roland xv 5080 and motif, respectively) in my book, but not horrible- just not my thing. it is an excellent machine, however, but overpriced as is most hardware.
the mpc is the premier sequencer/drum machine on the market. it really is the best, easiest and intuiive machine of its kind. no sequencer i have worked with comes close. great for drums and phrases, but its effects are limited, even with the card.
the combo is very powerful and as long as you can afford the required outboard gear it is an excellent core for a midi studio.... i myself would go the route of a motif rack and mpc (what i had before i sold it for my pc, cubase sx and kontakt) if i went back to hardware. it really depends on your sound preference.
really, an mpc and any first class sound module/keyboard is the best hardware combination OVERALL if that is what you are interested in.