I have read a lot about about canisters. At one point I was looking into adding one to my 125. A lot of people like the FX5 but there seems to be a lot of problems with them leaking. A lot of complaints about the "cheap plastic junk". I like eheim. I have not used any of their canisters but I do have 2 of their 1262 pumps and like them better than any others I have tried. Quiet, efficient, and continue to pump lots of water when the prefilter is dirty. Gotta think that their canisters are the same way. Just seems to me that most people don't wanna shell out the $ for eheim. The same thing goes with the Tunze line, big $ but great filters. I don't think that tunze has a canister. I have read where cleaning the FX5 is a pain, but don't know for sure. I guess like most things its all up to personal preference and your $. For myself, its Eheim or nothing.