Ian: I owned BOTH the E313 and E403. E313 is cheaper than E403(synth knobs) but the amplified sound is much better than E403.

E403 amplified sound is muffled somehow. But the cheaper E313 sounds clear but of course is a lesser keyboard with less features.

If E403 or the newer E413 has a clean sound then it is a very good keyboard. Those knobs are very useful in live situation.