Had my FX5 running since 2007-never had any running problems. Only problem is that a couple of the fastening screws bust (well the red plastic components) but this is easily replaced. Flow rate always stays good. I use Seachem and Eheim media and replaced the fluval foam (which is pants) with 30 ppi foam and noticed an improvement with mechanical filtering as a result. Cleaning the cannister is a chore but I don't do it that often (2-3 times a year). I do like being able to attach a separate hose to the output on the FX5 for WC-it drains 50% of my tank in no time at all.
I also have an Eheim 2078 running on the same tank (100G). I've been very pleased with this too. Flow rate does drop in time but is much quicker and easier to clean than the Fx5. I do think that Eheim;s are better made and more durable and if I had a choice I'd always go with them (but then I'm biased as I've used Eheim ever since began fish keeping 25 years ago!). I, like many, went with an FX5 as the price for the output was great. They were on special offer here in the UK and I paid £130 for it brand new
