Hi Rikki,
the SD1 styles play perfectly on the Midjay and almost no tweaking is required; I say "almost" because I don't like the choice of the programmers to set the "DX Rhodes" as the default sound for the left part of the keyboard, so I am forced to tweak at least that one sound.
Aside from this, all the styles play perfectly, but the same doesn't apply to older styles, like those from the MS series. While the SD1 had an utility to convert them, the Midjay lacks this one, so they are simply not usable. Pity...