I think bin cages are great for people who want to give their hamsters lots of space but don't want to fork out a lot of money, although I do prefer the way cages look.
For example, I bought 2 bins for £8 at a new store here and they measure about 3cm less than the rex each way, which is brilliant in my opinion! I'm going to sort them out and then use them for my babies when they come away from their mum - perfect
I did use bins at one point and loved them for the price/space, but the condition that I could have them downstairs was that the hamsters were in cages - not boxes.