If you want to create songs or parts without a computer and play them back in a "live" situation, the N364 is a fairly capable workstation, complete with disk drive, sequencer & arpeggiator.
If you want to program your own sounds, the AI2 synth engine is easy enough to control. Also, there are many soundbanks available in webland to augment the factory presets.
Are 61 keys sufficient for your playing style? Remember, its cousin the N264 has 76 keys.
How much or little do you want to spend?
Are you buying new or used?
If you don't need the workstation features, then perhaps the N5EX would be a better choice. It has the same synth engine, but with much more sound ROM and much better real-time control features and it costs less. I think it comes bundled with some MOTU sequencer and librarian software, as well as a sound editor.
[This message has been edited by Lee (edited 08-31-2000).]