I used to borrow the X5 from a friend and don't remember it having a sequencer or it being a workstation at all (no sampling etc).
The 01/W is a workstation I think (sampler, sequencer, etc).
I loved the X5... It is hard to explain what was special about it, but I enjoyed very much layering multiple patches and triggering them all at once. Great textures and inspiring pads. I used to just sit in front of it and play for hours on end.