the Mono/Poly and Matriarch are pretty different from the P4mer. mainly because they have a shared VCF and VCA for all the VCO’s, instead of being literally four of the same synth in one box, each with their own dedicated signal path. it’s a pretty unique thing. you can do the rotate through the voices thing with those two synths, which is great, but it’s pretty different from what the P4mer can do.
the closest is still the A4 probably. but not as much fun to play as the P4mer; having all those knobs in front of you all at once is just so immediate and encourages interaction and experimentation.
abother close option would be building a eurorack system with the Vermona qmi2 as your midi interface. it has some of the P4mer’s play modes in it. then you can customize the voices as you wish, or keep 'em all the same, or even patch it like the Matriarch or Mono/Poly if you wish. and you can build the system up as you get the cash, and do all kinds of experimenting with your options.
Luke Abbott uses it pretty heavily in his Against the Clock here:
