I'm in the Oly/OMD micro 4/3 ecosystem. I don't have the OM1, but did pick up a refurbed Em1ii a few years ago. Absolutely fantastic camera and holds up well even to this day. Yes the OM1 is an improvement, but I suspect it's only marginal for most shooters. I've bought a ton of used gear from MPB. Everything has always been in excellent condition and exactly as described in their listings. They show photos of the exact units they're selling so you know what you're buying. They have an Em1ii body in excellent condition for $600, which is an unbelievable bargain:
https://www.mpb.com/en-us/product/ol...pping%20clicks