I am going to either buy the fx5 or an ehiem pro for my new 125g saltwater.
The eheim pro is the quietest filter I have ever (not) heard. I literally had to put my ear on the canister to hear the motor running. It comes with a hefty price tag, but in the world of canisters there is a huge difference from the bottom, and from the top.
Marineland used to make solid filters that were cheap...now they just make them crappy. I wrote them a letter after receiving four filters in a row that didnt work. I wont buy anything from them ever again. Pain to set up, Pain to clean, and a Pain to deal with cause they break constantly. Plus almost monthly maintenance was necessary to keep flow rates high.
Let us know what you get and how it works out for you.