Sean: It's been a long time since I heard the QY700 and I don't know how it compares today. I remember that it sounded pretty good and it's the top of the line in the QY series but that's about all. Here's Yamaha's website for it (no demos though):
http://www.yamaha.com/cgi-win/webcgi.exe/DsplyModel/?gSEQ00005QY700