My favorite of those that I own is the Eheim Pro II, its a great filter and easy to deal with...but it was free. I don't know that I'd ever pay full price for a new one when I've had other brands that are significantly cheaper and seem to work just as well. As far as bang-for-the-buck, the Renas have my vote. Decent prices (well they used to be...haven't looked at them in a while), quick-disconnects, and lots of space for media.
For fluvals, I have a few running that are 10+ years old and starting to show some wear. They seem to be built very well, but they can be a serious pain to get primed, and I always get water everywhere when I open them. I'm guessing these issues have been mostly resolved with the newer models.
For fluvals, I have a few running that are 10+ years old and starting to show some wear. They seem to be built very well, but they can be a serious pain to get primed, and I always get water everywhere when I open them. I'm guessing these issues have been mostly resolved with the newer models.