I have two of them in my MIDI stack :-). I also had a DX-11 which was the 4-op keyboard and did patch design on that and then transferred the patches via Sysex

I have two of them in my MIDI stack :-). I also had a DX-11 which was the 4-op keyboard and did patch design on that and then transferred the patches via Sysex to the TX-4(s). It continues to be a great synth.