Deane good assessment on the SD7 I also had two SD7's....
sometimes the way you would use it on stage is totally different then what another player would do. I know you usually do not sing or use the VH combined with styles play or smf,mp3 backings etc, and that could be a reason for freeze ups also on occasion when you tax the OS and confuse it with too many duties at one time. Most times these things don't happen but sometimes they do and on stage is not a good time to do a reboot when an audience is looking at you...good to have an alternate device on board also, tablet, laptop to turn to and sing to a track while the reboot is happening which could take a few minutes.
You have to feel totally comfortable when performing with any keyboard. I enjoyed my time with the SD7's & all the other Ketron keyboard arrangers & modules I had which is pretty much all of them except the Audya I had,....
but I just prefer Yamaha to anything on the market at this time.
I hope Dave works it out and keeps it this time around...we'll see.

Take care