Let me add a few more words to my last post to give balance to my  enthusiasm over the CFS500. My enthusiasm is over the results of of the  CFS500 performance as a result of my modifications. If your going to use  the CFS500 in its stock configuration with the incorrect oversize  O-rings that make it very difficult to connect and disconnect and  maintain the stock surface surface area of 80 square inches where the  top of the filter is only exposed, then in my honest opinion your  probubly better off with the Sunsun becasue at least it is mod free  ready and has about the same exposed in-line surface area as the CSF500  stock. Also for those that just prefer in-line stacked-basket filters,  the Sunsun is the clear choice. 
But for those with an elementary understanding of "geometric surface  area filtration" and hydraulics, the CFS500 with its modified 300 square  inches of surface area, bottom pump design, relative high GPH, and ease  of maintenance for $58 make it a very exciting filter for those that  can appreciate and MOD it. Like the FX5 this filters industrial roots is  not for everyone.