Just thought I'd add my own thoughts on this cage since its already been reviewed very nicely
Back Story - I've had my cage for just over 2 weeks now, its technically my second cage but its the first one I actually put the new little fluff in (the first one was a rosewood pico cage but the bars were broken when I set it up so I never actually used it).
Since shes my first hammy since secondary school I'm still learning lots and rearranging the cage to suit her needs (its a work in progress).
I love how customisable it is, you can move the shelves around to a certain degree or remove some completely, you can change the layout of the tubes and remove the penthouse. I've actually removed all the tubes and the penthouse for now until Luna is more tame as I'm finding it easier to encourage her to come out and interact in the main cage area. She also pees in the penthouse so I'm hoping removing it temporarily will discourage this habit (although I doubt it will). I'll add the penthouse back and the tubes back in eventually to add more interest for her.
I found the accessories that came with it are brilliant, even though the cage is pretty pricey I reckon its not so bad when you factor in the cost of buying a wheel/potty/pods/bottle/bowls separately as well as a cage.
The biggest problem I've had is with the wheel, it started off pretty stiff so Luna wasn't really sure what to do with it and spent a night climbing and chewing the bars. I managed to loosen it for her by just spinning it myself and she loved it immediately, she then spent most of the next few nights just running on it. However, it makes a LOT of noise now. The spoke itself rumbles as she wobbles the wheel and the metal stand seems to sink to the bottom of the substrate and start tapping on the plastic bottom of the cage (probably my fault for not putting enough substrate in first time). Even now I've mounted it to the cage wall, it is still very wobbly/rumbly and I've had to put it very high so it doesn't scrape on the plastic sides. Its also a bit small for a syrian, although probably ok for a baby.
I have just bought a large trixie wheel and a large flying saucer which I'm hoping to alternate, although I'm having a little trouble figuring out how to fit them in (I'm sure I'll manage with a bit of juggling about). I may even take one of the levels out to fit it in and the customisation makes this possible .
I've had no problems with anything else, and although the picture instructions weren't particularly clear, I didn't have too much trouble putting it together in the first place.