The companion piece was the Yamaha RM1x which was intended to be the sequencer while the SU700 was intended to be a dedicated sampler with some sequencing capabilities. It was indeed intuitive and had some features like 'composed loop' pads which were instant resamplers that I still miss having once in a while.
Being a 90's machine it was quite limited in the amount of RAM it could access --- if I remember right the maximum you could expand it to was 64 megabytes. But to put that in perspective, DJ Shadow did the entire 'Endtroducing' record on a single 32 meg MPC2000.
Here's a --- LINK --- to the Yamaha home page for the SU700 and another --- LINK --- to the Harmony Central page.