I sing, so the vocal harmonies on the PSR 740 have been wonderful. I play a lot at nursing homes and for mental retarded kids. The challenge of playing for old people is unless they're really stimulated, they fall asleep. The staff doesn't like it when all the old people are falling asleep while you're playing. Well very few old people fall asleep while I'm playing the PSR 740. The styles are hot, the "sweet voices" sound so real (at least to me), it's very very easy to play and change styles and voices. The only downside is that apart from the 160 voices that come with the unit, you can only have three (what a pitifully small number!) user styles onboard at a time. Others have to be loaded from disc. You can load from disc during a performance (it doesn't take long), but it is kind of a hassle. And you can't use the one touch setting to get an appropriate voice for the user styles. You have to search them up. So to play from a disc takes about 10-20 seconds to search for the style and load it and find a voice for it. I bought the PSR 640 and then I exchanged for the PSR 740. Believe me, the extra poliphony, vocal harmonies, voices, modulation wheel, simple intro, simple ending, and organ flutes are worth it!