I know that Wurlitzer organ, well,The CVP 307 is an 88 keyboard digital piano with and arranger format, more money...and very diferent than the boards you mention.
The EXR7 is less $$ and NOT as friendly as the PSR 3000, aldo cost a little more, I own a PSR 3000 and you will also find more support not from Yamaha, but from users....like the PSR tutorial, etc.....I would consider the Yammi PSR.
------------------
mdorantes
_________________________
mdorantes