Yes, I know, I read it. Perhaps I didn't explain well my self.
There is a good arrangers at 1000 euros (ex. PSR1500, with smart card and USB device for to load hundreds of styles). So, the reason for OMB would be to be a cheaper way to have an arranger, because, if not, perhaps it has no sense to buy a midi keyboard which costs more than PSR1500 for to use with OMB.
So, my question was:
Which good GM/XG keyboard or piano costing less than 1000 euros would be a better thing (+ OMB) than a PSR1500? Better = better sounds, better styles sounding.
If so, as OMB uses Yamaha styles, is it better a keyboard with XG sounds than GM -like Roland- for your OMB?