I definitely have liked the fluval brand a lot as I have had two fluval 305's running on my 50 gallon for the last 6 years without any problem what so ever. The maintenance has been super easy and the flow rate has always been really strong and consistent and I have never had a problem with air getting into it. On the other hand, I have had my 125 gallon running this eheim g160-2075, and what a headache it has been, it seems so temperamental, and every time I clean it I am concerned that its not going to flow properly, or there will be air in it. When it's working its decent, but I need a second filter on there to make up for it and incase it decides it doesnt want to work one day. I'm not bashing all eheim's because I've heard good things from their classic series, but this one is sub par. As far as ease of cleaning goes, and disasembly and assembly goes, the fluval is much easier which is why I figured their FX5 would be a similar workhorse and easy to maintain.
"The FX5 is not a filter you want if you are after Bio Filtration. It is mostly sponge I have two and they are only ok by no means the a super filer if I had to give it stars I'd give it 2 1/2 to three stars. Biggest problem with this filter is ALLOT of bypass which can be fixed but then you will have to clean the pads in the Bio trays allot with me weekly and I have oscars in this 125 gallon tank."
hawkerw, I more than likely would be using the FX5 as a mechanical filter with a bit of bio in it, but probably would be using my eheim mainly for the bio. My water parameters have always been really nice with the eheim (definitely the thing I like most about the eheim). Would the FX5 make a superior mechanical filtration system in your guys opinion, or is there other filters just as good as it? (Brand loyalty aside because I couldn't care less what the name on the filter is, its all about its function and reliability etc)