Late to the thread ...

A couple of comments. The Thorne's Everynuc is pretty good. Best if you use Langstroths, but they convert it to National sized using an internal feeder. The walls and the roof are good and thick and strong. The entrance is too big and the bee space is a bit off at one end. Nevertheless, the bees do really well in them overwinter.

2 in 1 nucs are an accident waiting to happen in my experience. I made half a dozen or so a few years back, filled them with virgin queens (one each ... and bees!) and ended up with about 7 mated queens (of 12). Usually the queens manage to sneak over the divider (under the crownboard) and slaughter their neighbour.

My advice would be to dummy-down a normal 5 frame nuc - two frames and a dummy board are usually fine - and not worry about the queens running amok.

Looked after, a poly nuc should last ages and pay for itself in a season.