I know nothing about the brand Polyfusion other than the fact that Steve Porcaro had a monster modular setup with Polyfusion modules.
Has anyone here had any personal experiences with Polyfusion equipment? How did they compare to Moog or Buchla systems?
They are very rare machines - rarer than Buchlas. I don’t think even Kevin Lightner (RIP) had one in his shop.
During the 1970s a couple of Moog engineers proposed improvements to the modulars and were rejected, so they quit and started Polyfusion to build their own systems. They had some interesting modules of their own design - sequencer, VCO, VCF, and one of the first voltage controlled EGs. They also had a polyphonic scanning keyboard controller with a big box for the eight sets of CVs and triggers, unknown if it was their own design.
Polyfusions use the east coast subtractive synthesis ala Moog/ARP.
Not much in the department of Polyfusion clones. Modcan cloned their lowpass filter, DotCom cloned their sequencer, and that’s about it. I heard audio samples of this filter and it does sound unique, not at all like a Moog or ARP or Oberheim filter. I never understood why no one has cloned the VCO - the interface is ideal with the pushbuttons to select the octaves.
Besides Steve Porcaro, Mel Wesson also toured with a Polyfusion modular. His modular was put in storage for months, then pulled out for a tour - and was perfectly in tune.
Polyfusion still exists and they have retained a modular for their main conference room, but have left the modular business back in the early 1980s.
Mine polyfusion System ! .. I know a lot about em … Kevin Lighter sent me all his data about PF few weeks before he passed away
Original VCO rev A and ones I made ( I cloned - not exactly good way to call it ) … I made replica of many modules (but system i have is 100% original beside cabinet i made for it!
left is made by me .. right is original !
and a bunch of em !
Cabinets we made here
cabinet made for my modules !
some DADSR ! replica
only weak spot of Polyfusion are original design of DADSR .. so I designed new ones based on SSM 2056.. and those are lightning fast 
I replicated ..
cabinet
VCO rev A
VCO rev D
LP filter
HP filter
Phase shifter
Variable formant filter
VC LFO
Random signal generator
Dual VCA
DUAL DADSR
Mixer
and made my own design for VC DADSR with SSM 2056
and here it is
as far as Kevin told me .. made 11 of em and worked on like 15 of those monstrums .. he made one that is now owned by Deadmau5 and made some custom modules for Hans zimmer ..
he bought leftovers from PF somehow .. and made a lot from parts and leftovers .. he also sent me a doc on modules he made from scratch .. like VC DADSR based on CEM 3310, and some other stuff!
also Modcan made updated version of VC LFOS !! 
her are some monsters Kevin worked on !
all this pictures came from Kevins Hard disk .. he sent em all to me personally
ModCAN Polyfusion VC LFO !
I have original PF VC LFO and had MOD can one for long time .. also Bruce send me some docs on it .. bruce made great job ad improved it a bit .. polyfusion VC LFO is fantastic sounding VCO too!
demo is here ..
Wow, thanks for the info roginator!