A little late to the show, but I'll play. Here's what I know (or think I know!)...
The Kareens are not exact clones, but close, akin to the FEGs. They are commanding a little less than that, especially since it's so beat up. I recommend finding a good deal on a transfer and buying a Kareen or FEG from Sarco online. The prices from them can't be beat.
The FMs are made under license and are factory approved by FN, also having been made on FN equipment. Albeit the "rough" finish, as opposed to the originals and the Kareen/FEG, these are correct Hi Powers with full parts interchangeability. These are costing a bit more these days and I can't find them for the same price as a Kareen or FEG, but from the sources I've seen it's because the FMs are more sought after.
It might be interesting to note that I stumbled on this thread because I'm doing a little reading in anticipation of the FM Hi Power someone is selling to me tomorrow afternoon for $400 OBO. It's not the price I want to pay, but the FNs and Brownings are way too high and, all things considered, it's not much over the price of one a year or two ago. I'm seeing the FMs on Gunbroker anywhere from $350 or so to $750.
"Shut up, crime!"