I have a cube and LOVE it. We started with an ark we built from plans. It was OK, but didn't have much room up top for my girls (RIR, BR, BO). The top is not super spacious, so I don't think I would put more than a max of 5-6 larger chickens in there. The entire floor is the "roost", so they can sit anywhere. I got an extension to the run so I've got about 8 feet--but would add more if I had many more chickens. I've found it to be relatively sturdy and it is just so easy to maintain. Because it's plastic, you can just dump out and hose off the droppings trays, and it opens up nice and wide to make it easy to really keep it neat. We had a mild winter here in NJ this year so I can't attest to how it would fare in really cold weather, but prior to purchasing I looked around on here and someone had posted a pic of theirs covered in snow and doing just fine! I find it to be relatively easy to move--just push the wheels down, which elevates the coop and the run. Steering is clumsy, but I can move it alone which is nice. No problem putting it in the garage for the hurricane last summer. I have had no issues with predators in my yard (knock wood!!!), but based on the construction I do believe it would hold up and the covered run is an advantage to prevent hawk attacks.
Downsides: It is definitely expensive, and for the price it arrived at the greyhound terminal a little scuffed up. Not damaged, but for $1000 I expected perfection! (Also pick up at greyhound was not easy in our area--picture double-parking the SUV on a busy street in downtown Atlantic City, NJ and making several trips out with giant boxes with no help). It also was a bit of a pain to put it together. The interior size is of course not expandable, but the run is. The food and water containers are just OK-- I don't like the water being so wide open from above. However, they do hold enough for several days. Also-- the ladder to the coop does not go all the way to the ground. I'm not sure if bantams, etc would be able to hop up there?
Overall, if you don't mind paying for it and are only planning to keep about 6 larger chickens, I highly recommend!!! (With run extensions and/or smaller birds, might be able to add a chicken or two.) I went with it because I do not enjoy the maintenance, and it's really terrific in that regard. Two seconds just to empty the dropping trays into a trash bag; maybe 20 minutes for a full thorough clean of the trays, floor, and nest box. My girls seem very happy.
Hope this helps!