I have been using an ant cube XL nest (20x20) with substrate for my carebara diversa colony and previously for my messor barbarus colony and for both species it held up really well. In my opinion, Its definitely one of the more aesthetically pleasing nests on the market( aside from AAC nests and THA’s stuff) and it’s great for looking at the different nesting structures of different species, like carebara diversas massive, deep chambers, though chamber size and shape is still determined by the relative width of the nesting space. Obviously, you are sacrificing ‘some’ visibility but as long as you are smart about the size of the nest you pick, you can still see a good portion of nest activity.
The few issues I have really noticed is that the nest retains humidity really well due to the lack of ventilation and mold builds up easily. Further on this point, when it comes to hydrating the nest, there are two hydration holes for inserting a syringe; a good idea in theory but for smaller species or colonies that dig deeper, it’s hard to hydrate without many ants escaping, though it must be noted I’ve only noticed this with my carebara diversa colony. Furthermore, you have got the extra cost for buying a syringe as most plastic pipettes are not going to fit. Moving a colony out forcefully is not really a great option with these nests either and can risk damaging brood. They do have nest inserts to deal with this issue, though as far as I last checked, shipping for these is only available for within Germany (aside from the 20x20 xl), though this would probably change if a USA supplier is importing their nests en masse and if I recall correctly, these inserts are only available for the XL sizes at the moment.
Moving a colony out forcefully is not really a great option with these nests either and can risk damaging brood, so I’d advise being careful on the size of nest you pick, thinner nests being easier to dump colonies with. High cost is another big factor that I have seen a few other people mention before, though I think if you just stick with the basic nest and/or arena combination the cost is relatively decent. I can't really comment on the arenas but from what I have seen they are pretty great, with some helpful customization. Also, Antstore only currently ship within the eu, so you would be having to wait until a supplier becomes available with the USA (which won’t be too long going off what Canadian anter is saying).
Prawn and Mayo sandwiches taste nice.