Do let me say that while this is a cage that's "made" for ferrets, I house rats in mine. It doesn't change a lot, though!
I love the Ferret Nation (double). It is the last cage I will ever need to by. It is large enough to house 12 rats, is extremely sturdy (most sturdy cage I own - and I own a LOT!). The Ferret Nation has wonderful storage built in, is on wheels for easy moving, has SO much space to hang all sorts of goodies... The shelves are adjustable to either side of the cage and can be at 3 different heights... The list goes on and on!
The BEST feature of this cage, and one that sets it apart from the rest is the fact that it is completely accessible! Doors in both sections not only open all the way, but they come off as well! That is, hands down, the best part of this fantastic cage.
The cleaning of the cage couldn't be easier. Simply remove the items (easy with complete access!), pull out the pans and shelves/ramps (SO easy to clean) and replace. No other cage takes so short. The only thing that takes time is decorating. ;)
I've been through MANY cages and the Ferret Nation is, hands DOWN, the best cage out there. Ferrets and rat owners will LOVE it!
(A tip - if you have small female rats or young males, you will need to modify the cage as the spacing of the bars is too big. Totally worth it! Use hardware wire and zip ties for easy removal.)