Hey, I returned my SU200 and picked up an SP-303 (the SP-505 was not available).
I use it for triggering samples live, not really for sequencing (got a computer for that), but apparently, there is a way to record your 'button presses' into a pattern and make a song.
The ES-1 I played with was a little trickier to use. It was more of a sequencer than a phrase sampler.
The SP-505 seems along the same lines, more of a sequencer. But, it all depends on how you are going to use it.
I do know the ES-1 only samples at something like 31 or 32 Khz. The SP-303 (and I'm sure the SP-505) do it at 44.1Khz ("CD quality").
But again, they are both phrase SAMPLERS. You only get out of it what you put into it. No on-board sounds.
[This message has been edited by splatastic (edited 11-24-2001).]