Scott suggested the DGX505 if you need 76 keys, but actually it's the DGX305 which has 76 keys. The DGX505 has 88 keys.
I sell both the Yamaha and the EXR7 and because of price I sell more of the Yamaha's but I personally like the EXR7 alot for many reasons. First, the EXR7 has a 16 track sequencer to record your own songs and the DGX can only record 6 tracks. Next, there is a section in the styles called "flash" memory where you can store about 100 of your favorite styles taken from the internet or any style disk available. The EXR7 features both a floppy disk drive and USB. I also like the cover band feature on the EXR7. You can play a style and with the touch of one of 5 buttons you can change all the voices associated with a particular genre of music. And, you can also do this while playing a midifile. I also think the acoustic piano sound in the EXR7 is a warmer piano then many of the lower priced models. As to the user interface, both the DGX and EXR7 are about the same in learning how to use.
George Kaye
Kaye's Music Scene
Reseda, California