I use Mixbus for mastering quite a bit but I have not had too much problem recording live bands and church choirs with it. I don't look at it as ever being able to compete as a full blown DAW. It does serve well as an old school no-frills audio recorder though.
Yesterday was the first time I have ever really had a major problem and I'm not sure why. I tried the PortAudio-No Callback setting early in the morning and it crashed hard all day. I went thru h#$% all day yesterday trying to figure it out and then after talking to Ben at Harrison I tried that setting again. Mixbus fired right up and is running fine since. Go figure!
Scoble, I had no trouble with any versions of Mixbus up until 3146 yesterday. Ben said yesterday that they would be testing the Roland interfaces with Mixbus in a few weeks. Maybe if you tried the setting I did that solved my problem it could work. I know if it doesn't how much a pain in the $%^& it is. The new monitoring section in 3146 is worth the try.