Sorry! It's maybe more a list of "usuals" than favourites
The Fuzzbutts ones are very well made - no loose threads etc. The hamster ones do have a second entrance hole/exit at the back in one of the rear seams - which is nice for them and fun for them. Except when you're wanting to use it to transport them. Or lift them in and out of the pet carrier. I use a bulldog clip to close it off then.
I have used them particularly when taking a hamster to the vet to be pts. They will always go and retreat to their snooze cube at the vets. The vet can carry them away in it and put it down in the gas tank (sorry). I like to think they feel safe and cosy and unaware and just go to sleep.
All our hamsters have loved their snooze cubes. I leave it out on the sofa during sofa time and they can dive in and sit for a wash if feeling they need to retreat somewhere. Only for out of cage use though as they're fabric and fleece.
I have used them in the cage with a very elderly hamster before - who isn't a chewer (and beyond chewing usually). Our first robo loved going in his when he was older and it sat in front of his house door. It was the only way I used to be able to get him out of the cage easily without him bothering. Just put my hand over the door and lift the cube out.