Those Hagen Vision cages look nice, but I've never used one personally. I can see the pros and cons though. Funny... the first time I saw one at a store, it's clean modern design caught my eye. I felt like a moron for as long as it took me to figure out how you'd clean the bottom with no pull out tray.
..then I thought, well you must have to lift the top off since there is literally no other way, but no, that just doesn't seem right