Upper Levels Loft or no loft for c&c cage?

I think it really depends on the size of your cage. I briefly had a loft that I used as a kitchen for my girls. While it made a significant difference in the hay mess on my cage floor and made for easier cleaning at the top level, I found it extremely frustrating and difficult to change the bedding under the loft. Keep in my that my cage is large (4x5 with 1x2 extension). My girls also had a tendency to sleep in the back corner under the loft and pooped there, making a huge mess that I had to struggle every day to reach. While it's great to give your piggies extra space, remember also that the ramp can take up a significant amount of running space. I'd say for a smaller cage with the ramp on the outside, go for it, and for a larger cage, stick to extending the bottom level.