Finally, unless you’re specifically into 80’s hardware synths, I can strongly recommmend Oli Larkin’s excellent VirtualCZ. I was able to tranfer patches I had made on the original and recorded on paper (in the “Sound Data Handbook”) into this VSTi and reproduce the sounds precisely.
On the other hand, the hardware CZ-1000 is a lot of fun to program manually – just remember to do a reset when you fit the batteries, otherwise the pitch will be off! (the procedure is in the CZ-1000 manual).