Howdy Zave,
Well, I've never used the Hydor Canister, nor have I even seen one. I have used and continue to use Fluval Canisters. I have four of the 04 series, and they're great. I like the "Aquastop" feature and the ribbed hoses. They offer flexibility with choice of media. They're nice and quiet and do a great job. They can be a little finicky when it comes to reassembly after cleaning, but after a time or two, no problem. There are four models. Prices range from about 50 bucks up to $180.
I have a couple of Kangde brand filters, that come under various other brand names as well. They are quite large with huge media baskets. There are 3 models available as far as I know. They operate quietly (silent; I have to put my hand on it to feel it running)and efficiently. The hose connection is a match for the Fluval hose connection valve assembly. The intake and outake hose valves have idependant off/on; different than the Fluval Aquastop. However, the valve assembly from "Kangde" and clones is interchangeable with Fluval. I can't recommend these units yet, as I'm testing them, and have no idea as to longevity. I can say that so far, I like them. I've no idea what these are priced at average, as I've seen them priced at all levels. Mine are on loan from a wholesaler/reseller.
I've owned a couple different models of the Eheim Classic. They're a complete and total mess to clean. They're a huge pain to get primed, started and continue running. I'll never own a Classic again. I understand the Pro II models are quite good, but I've no experience with them. Way overpriced for a molded plastic box, with a few plastic racks or baskets, and a $10 motor.
The Rena Filstars are very popular, but it seems they develop a leak problem at around a year of operation, give or take a few months. They're also noisy in comparison to most of the others. Still, most seem very happy with them. I think pricing ranges from about $80-180.
The PennPlax canisters don't seem to be very popular, but I've read comments from several users who are pleased with them. I've also read a few negative comments. Judging from what I've seen in the store, they're well constructed. Price?
The Marineland Magnum canisters do a good job, but aren't up to the task when compared to other larger canisters as above.
My favorite filter is the Jebo Odyssea CSF4 (838). It comes filled with media; nothing to buy. It has a spraybar, as well as intake and outake siphon tubes and hoses. The valves are independant and pivot. It contains four media baskets, and has no bypass. The motor is quiet, the priming button large, and moves about the same amount of water as the competitors. It is my understanding this unit is a knockoff of the Eheim Pro II. These are available from many retailers and online for as little as about $50 shipped.
There are also some HOB and overhead wet/dry filters that do a great job, and I use a couple of those independantly as well as together with a canister on larger aquariums. However, as far as just a canister goes, my vote is with the Jebo.
