I only have SIP, 106ff, and FP. I got the FP from another member and I havent used it yet. I also have OP. SIP does more cutting faster than OP. SIP has a pretty good working time, but nowhere near as long as OP. I like OP and it's great to mix in with something that has flashes quickly so you can get some more working time, but the last few details I've done have been polished with the SIP and 106.
FWIW,
People have been reporting issues with
Menzerna being picky about weather conditions, and I've never had that problem with OP (or Menzerna either, but I've used OP alot more).