The Yamaha PSR-E403 keyboard has been replaced by the Yamaha PSR-E413 as of May 2010. The two models look almost the same and are EXTREMELY similar in terms of features, though E413 has a few upgrades (165 vs. 155 styles; 100 arpeggio functions vs 50; etc..). The two are so similar, in fact, that purchasing the PSR-E403 at a respectable discount below the PSR-E413 is something new musicians on a budget should consider. Check around for the best prices and then make up your own mind if the upgrades are worth the additional expense.
EXTRA FEATURES: Sure, you could buy a real basic model for less, but sooner or later you're going to wish you had a few extra sound effects and knobs to tweak. The Yamaha has a nice display with a blue back-light, which makes it easy to see which note you're playing.
SOUND: Plug in some Bose 2 Quiet Comfort headphones (worth every penny, believe me) and you can bang on your keyboard all you want without disturbing whoever is next door to you. The sounds and sound effects that this keyboard produces are really amazing, everything from pianos to church organs to brass, world sounds, guitars, choirs, drums and special effects.
EASE OF USE: The basic actions like playing the keyboard itself and selecting a "voice" to use is really straightforward. However, other actions like transferring data to and from the keyboard to your PC is still a puzzle to me (granted I haven't tinkered with this that much). And as I'm still a beginner, there are lots of functions I have no clue what they do or how to use them, which is good in a way, because that leaves you something to discover later on, giving your keyboard more "replay value".