I've been using Marineland Penguin 330 BIO-Wheel filters on my 27 gal. and 39 gal. tanks for 8 years now and I love them! These are the older models now, but I see no reason to upgrade to the new models. Replacement parts, if ever needed, are still available on the Marineland website as well as many local pet stores.
They work wonderfully, as far as I am concerned. I am quite happy with the fact that I don't need to buy the costly packaged replacement filters, I can use plain filter pads cut to size. They're very quiet and there's rarely any maintenance besides rinsing the filters.
I'd definitely recommend these.