AR of some flavor although I have an AK as well. Why AR over AK? I built both. Unfortunately didn’t realize problems with Tapco replacement triggers for compliance parts. So, my AK is legal but doesn’t yet function like an AK. That is, the bolt drags over the replacement hammer and fails to come completely into battery. A few hundred more rounds ought to solve that problem.
In the US, the AR just makes more sense. The ammo of choice will be 5.56, not 7.62×39, and there will be plenty of it. There are plenty of magazines available. As long as the .mil is supplying things that run on 7.62×51 and 9mm, they’re worth having as well. Personally, if it came down to just carrying weight I think I’d rather have a couple more mags than a handgun.