I own the cfs500. Lots of people do. With a few modifications it has amazing potential and offers tremendous value.
upon purchasing one, make sure to get some cheap #17 danco o-rings for the top lid ports where the orange valves sit on because the stock ones are too fat and stress the plastic to its breaking point.
Also don't over tighten the lid because it deforms and I now have to silicone it on due to leak issues. But that was my mistake.
For the price, you can't beat this filter.