So I guess I should have prefaced the belt fed comment with the obligatory I own a half dozen semi only ones. Including a 1919 and M3 so I am covered in terms of spares, barrels, links, ammo, and tripods. I have a proper M3 tripod, an MG3 AA mount, and a buffered Israeli MAG-58 tripod. Only thing I don't really have on hand are dedicated linkers for each gun. Also I spend way more time tinkering with my toys than I do shooting, hence my preference for mechanically complicated but interesting operating mechanisms. Having the time and space to get one just right is a good part of the fun for me.
I am sincerely leaning towards a transferable or pre-sample Uzi or possibly save up for the AR-15 suggestion, which is always a popular choice and I can keep one running forever. But the nagging sensation is telling me to snag up one of the MG34 pre-samples that seem to be available at the current time.
Also is there a particular reason to avoid a MAC if the plan is to either buy it with or immediately purchase a Lage upper?
Thank you all so much for your time and suggestions!