I went crazy with FM...I had a DX7 first, sold it and bought a DX7MkIIFD and then I added the TX-802 (which is a DX7MkII in a rack), which was MIDI'd to it.
I also had a MkIIFD stacked with a Roland D50 (with a PG1000), two great 80s synths and still my favourites to this day. (Not for recreating true sound, but as pure synths for awesome pad, lead and bass)
cause as you know, FM does organ sounds like nobody's business.
FM sucks at Hammond, but it is Fantastic for Organ Bass in dance/pop music