equipment - detail
The main reason I bought this synth was for the arpeggiator. I had just discovered the usefulness of one after buying the Roland SH101 and thought, "I'll have to get one of these that works with MIDI!" This had just come out and there weren't many new synths at the time with one, especially one that could be MIDI clocked. As a controller it is excellent, the fancy mod wheel/ribbon barrel is great for adding movement to sounds. It was my main controller keyboard for a few years, up until I got the Novation Supernova II keyboard.
The on-board sounds sound great and many unique sounds can be produced from the powerful digital modelling synth engine, if you've got the time to spare. I generally use SoundDiver for programming this very 'deep' synth rather than getting lost in the multitude of parameter pages within the synth itself.
In some ways it was a shame that it was only monophonic, but you knew that it was a 'solo' synth when you were buying it. Korg did bring out the polyphonic Z1 a year or two later though.