As I see nobody has reviewed this cage yet, I thought I would add my review. I should point out that I am no longer using this cage - because of bar-biting and the fact that a wire cage allows my cats to get too close to my hamster - but if neither of those are issues for you, it's a good choice.
As we all know, it can be hard to find cages designed for hamsters that actually offer them enough space to live in, especially in the USA. Disheartened by my previous attempts to construct a good bin cage and aware that my young Syrian was trying in vain to find things to climb, I set out to find a decent wire cage. Not an easy task it seems - when enquiring about a variety of cages made for larger animals I was told quite abruptly that they were much too large for hamsters (more to the point, the bars were spaced too far apart). Then I found the Jack 72. Priced in most places at $70 and up, it was not a cheap cage, though I found it on Greg Roberts Pet Supplies at $54, which seemed quite reasonable. (I would definitely recommend that site, they are also quick to deliver).
Putting the cage together I found everything rather flimsy. I had read reviews to that effect so I wasn't too surprised and was careful not to exert too much pressure and make anything snap. A clip had already broken off the corner toilet but it’s still perfectly functional. Overall, the cage was distinctly fiddly to construct - in particular the tubes, which you have to screw into the holes. Once it was done though, I was quite pleased with the result. Admittedly, I did have to discard certain elements immediately - the water bottle leaked everywhere, and the wheel did not attach to the cage properly, was thin and bendy and made a racket, so initially I switched it with the silent spinner I already had, which fits perfectly. (However, that too was too small for my Syrian, so later on I ended up taking one of the platforms out of the cage so that a wodent wheel would fit). The house that comes with the cage is also a little small for a Syrian, and I replaced it with a house under the platform. I also had to use cable ties to narrow the gap between top and side panels in the middle since the corner clips did not seem to hold together tightly enough.
(This is only a very temporary water bottle. My "final" layout, which I don't have a picture of, was with the right-hand platform a little higher, a house underneath it, then the left-hand platform removed so that a wheel could sit on a stand there.)
Overall, my hamster seemed very content in this cage. He loved to be able to climb the walls and go through the tubes (these might be too small for a very large Syrian), although we did have some bar biting issues, regardless of how many other distractions the cage contained. With dimensions of 28 x 17 x 16'5 ", he has plenty of space to run around (and my only difficulty is finding somewhere to put the cage!). I am not convinced that the cage is as escape-proof as some, as the doors could become quite loose, but fortunately my Syrian does not seem to be much of an escape artist.
The Jack 72 is not as easy to clean as my Ferplast Duna, tanks or bins, since you cannot simply lift the top off and set it down somewhere, due to the tubes that stick out below the wire section, nor on its side without detaching the food dishes and water bottle. You also have to unclip the platforms and remove them for washing – taking the tubes out for washing is also a major pain as they are incredibly hard to snap back together. Another noticeable inconvenience is that it is quite hard to get the hamster out of the cage – although there are three doors, these are quite small and you can’t reach all areas, e.g. under platforms, from them that easily.
In conclusion, this is a great cage for size and variety for the hamster. If you are looking for a very sturdy, durable cage, however, I would not recommend it as strongly. For $55 (under £30), it does seem like quite a good buy though.