Doggiehowser,
I also owned the XDS-1 before the MPS-5. The XDS-1 have a slightly better mid band with vocals but loosing out to the MPS-5 slightly with a darker back ground, detail, 3D, resolution and dynamics IMO. The XDS-1 do have a deeper soundstage like listening from the 15th row whereas the MPS-5 brings you slightly closer 10th row. Saying that, the MPS-5 have a MUCH wider 3D soundsatge.
They both are great players and synergy with the rest of your system will play a big row in choosing which to go for. The MPS-5 ultimately is a cheaper machine which is a big plus.
Cheers