I would pretty much echo DonM's findings...except the OS category..

I think folks are confusing what they are use to ...and the best OS..

OS can be different things to different people..

I find Yamaha to be one of the least favorite OS...and Roland the best...why because I am use to Roland and prefer it..

Some of the OS has to do with saving and loading data...another area can be features..and another the ability to get around...another the ability to edit[and in a live situation]...Roland excels in all of these....Yamaha does not..Korg does not...Ketron does not...

Think about what I am saying with an open mind...