I had the CPR large aquafuge with light fixture on my 55 until I upgraded tanks and I loved it. I had it behind the tank, so you couldn't see much of it from in front of the tank except the intake powerhead and the output. However, those parts of it looked pretty clean like most CPR stuff (in my opinion). In short, I loved it. It holds just under 5 gal of water, which is like expanding your total water volume by almost 10%. I had chaeto growing in it and definitely noticed lower nitrates within a few weeks. There was also about an inch of live sand and a few pieces of live rock which had pods on them. I found myself craining my neck over the tank looking at the fuge so much that I seriously considered hanging it on the front of my tank. In short, I think they a good thing and definitely recommend the CPR ones. They aren't cheap, but they are less than some brands and are really good quality. The light fixture you can get with it looks nice and works well (the chaeto was growing like mad). Good luck.
