After a couple of recommendations I got curious and got myself a little 1986 KORG DS-8 to try out....
I am quite taken by this inexpensive little beast!
The DS-8 was unusual in that although it was based on a 4OP Yamaha FM chip set it was presented with a somewhat more intuitive and user friendly programming interface which is quite a lot more inviting to experiment with than a classic FM user-interface! The synth also featured a detuned unison mode and some useful built in effects such as chorus and flanging which give the instrument quite a different feel.
I have just had a go programming some new patches on the little beast and I'm quite encouraged considering how awful the factory presets were!!
Here is a quick test recording of some of my new patches...