If the EXR5s is the same or similar to the EXR5 that I remember when I was working for a Roland dealer a couple of years ago, and it was between that and a PSR-S500, I would without question go with the Yamaha. As far as easily muting tracks, if it works like the other previous models, then muting tracks would be super easy. I did that all the time on the fly with my PSR2000/3000/Tyros 1 and now Tyros 2.

As far as the EXR5. If somebody had one for free to give me across the street, I'd have to think about it before I walked that far. In other words, not a terrific keyboard. I am not saying for the right hobbyist that it wouldn't be a great little keyboard, but again, comparing with the Yamaha and what you want to do with it, no contest.

Scott
http://ScottLMusic.com