W7/Vista Client - Fact or Myth?

Since JMS worked to a degree on Vista/7, I'm not sure if it was the BB patch that improved the situation but JMST does run on Vista and Win 7. People have told me there are severe problems like the chat being illegible (but Japanese characters are pretty illegible on XP too) and disabled menus but gameplay seems possible.

GMS has always been playable on Vista/W7 (exception of 64 bit version where DCing is pretty much once every 10-15 minutes). I think the main concern here is about multi-phase bossing and not DCing during them...as well as 64 bit OS compatibility.