I've got a Model 1 upper that's a great shooter:
I've been using it on a Noveske lower with a Geissele DMR trigger and an Aimpoint CompM4. It's easily one of my favorite rifles.
Currently I'm contemplating a lightweight 7.62x39 AR build, but I'm unsettled as to what that will be.
For mags I've used:
• Standard 5.56 mags with 7 rounds - OK
• MWG plastic 5 & 10 rounders - did not feed at all
• National Magazines 17 rounder (looks like a regular 30) - did not work at all
• 20 & 30 round USA "frankenmags" (20 such in the picture) - work great, but out of production and hard to find
• Colt 7.62x39 5 rounders - work fine, but only 5 rounds
• USA 10 rounders - work OK, best when only loaded with 8 rounds
• C Products 10 rounders - work just fine
I ordered my C Products 30 the day they were announced as being for sale, over a month ago, but I haven't heard anything since.