"The only thing it has over the PSR1500 is the 76 keys", said Starkeeper.
I think it is not so.
I think EXR-7 has far better keys, has far better piano voice, some voices are better than 1500 ones...
But you are true. EXR-5 is bad in functionality: you can't modify style parts, edit them or create styles. And its screen likes made 30 years ago.
But, for a pianist, is a lot better to play it than these smaller and filmshy yamaha keys