I recently purchased this cage after considering many others. It is a bit more expensive but you get what you pay for. It is plenty roomy for my female ferret, extremely easy to clean, which for me was a major concern as my ferret is still a baby, and these lovable little things require some patience for litter training. Easy access double doors swing wide and are ferret proof. 
It is large and does require a bit of space, but with the included casters, it's very easy to move around. Assembly was not difficult, and no tools were required, but go slowly and pay close attention to the illustrations when you put this together.