I've tried to be objective and rate it from the viewpoint of someone used to more professional gear... this is why I gave it a "good" rating in many places instead of "excellent." But for the price, it's probably the best home-type keyboard Yamaha has ever made. (Their follow-up model, the PSR-520, has better voices but is far less versatile and is incapable of many things easily accomplished on the PSR-510.) Oh, and one thing more: the 100 built-in Auto Bass Chord rhythms are among the best you'll find anywhere in this price category.
Comments About the Sounds:
Many of the sounds are quite realistic; just as many are not, but are generally usable. What makes this unit so special is not its sounds so much as its versatility.
(Thanks to Apollonius for this info.)
and RATOBASHER for the pic