XP was crappy - it hit the disk so often and hung.
DYI http://www.gearslutz.com/board/electronic-music-instruments-... although you'll have to wade through some non-techie voodoo interpretations if you peruse the whole thread. Also, bear in mind that this is a particularly fussy demographic. I sometimes think if you are that obsessed then maybe MIDI isn't the protocol for you, but OTOH there isn't much in the way of OSC hardware on the market :-/ It's notable that there's a bit of a CV renaissance underway though, a lot of people prize timing/resolution over versatility.
If it uses ASIO MIDI back end it'll miss all the problematic message loops.
I only use SYSEX and use the Triton Studio sequencer though as its the most awesome thing ever made by man.
Of course I could get a Mac, bt I'd really rather not switch platforms or buy a bunch of extra expensive hardware for this one purpose. I could also run Linux, but until very recently the selection of music production software has been poor.
That said, I don't have any complaint with MS about their decision to abandon the platform, I think they've done a good job in supporting it this long. I do wish they'd rethink their driver priorities though, MIDI has been around for over 30 years, and being 7-bit ~32kbps it can't be that hard to get decent realtime performance.