re: canister filters?
Well.......you have a lot of choices, and thankfully, most of them are pretty good.
Marineland
Besides the hang on & Eclipse overhead filters, there is the HOT Magnum canister. It works as advertised, and has some flexibility as you can use carbon, ammonia pellets, or bio media in the basket along with the sponge sleeve. You can also use the pleated filter (much like a drinking water type filter) for quick cleanups and water polishing. The 250gph HOT is light and fairly compact with a power button on the unit itself. This is a great filter to move from one tank to another. Don't expect this unit to do as good a job as larger canisters, though.
Fluval
The x04 models are very capable of providing excellent water quality and the 204 would work for you. I'd be more inclined to use the 304, however. Many complain about the difficulty of cleaning the units. I don't find it difficult at all. The aquastop feature (water shutoff and flow control integrated into both in and outflow lines)is a very nice touch. The 304 has a foam sponge divider with directional flow and 4 sponges, and 3 divided media baskets. The smaller 204 has the same type sponge divider insert and 4 smaller media baskets. The ribbed hose (which some don't like) is an awesome part of the system as it doesn't kink or sag the way simple rubber or vinyl hoses do. The priming system on the filters works well. These filters are very quiet. I have read a few reports of failures, leaks and problematic operation with the 404. Fluval now has x05 models available. I don't know what the changes are, but they look the same.
Jebo and Clones
The Jebo 838 (slightly smaller version available), aka Odyssea CSF4 is a knockoff of the Eheim Pro II. It is a very large filter that will move about 300gph, give or take with no media installed. With media, expect to get somewhere around 160-170gph; a much more realistic figure, and comparable to what any of the other "top-of-the-line" filters achieve. The Jebo (Lifetech, Odyssea, Newport) comes with four huge media baskets and all media including filter pads, sponges, ammonia absorber chips, carbon, and ceramic bio media. It has a huge priming pump, just like the Eheim. These filters are nice and quiet, and also come with a spraybar. Although somewhat new to the US market, products from this company are widely used globally with very good results. Spare parts for these filters such as impellars are just starting to appear in the marketplace.
Rena
The Filstar line of canister filters is probably the most popular outside of Eheim. Everyone seems to love the job they perform, ease of cleaning (although it's pretty much the same as all the others), and cosmetic appeal. These filters do get a lot of complaints about the noise they make. Another notable complaint is that many of these filters at or about a year of use start to leak from the area of the power cable. Rena's customer service has been attentive to this problem, it seems, by sending replacement parts at no cost. With as many failures in this design, it's remarkable the filters are still so popular and that Rena hasn't changed this flawed design.
Via Aqua
Nice filters with the modular design and similar to Rena. Some complain of bypass. More popular globally than here.
Penn Plax
There really don't seem to be enough of these in use to render a valid opinion. I've seen comments ranging from praise to absolute hatred.
Eheim
This is the granddaddy of canisters, and has the reputation as the finest filters available. I believe most of the popular brands do an equally good job of keeping the water clean. I also believe Eheim filters are grossly overpriced. Granted there are Eheims in use today that have been running for a decade. But, there are others that also enjoy this kind of longevity. The Eheim Classic line of filters are horrible in my opinion. I owned a couple of them years ago, and they were simply a mess to clean, and incredibly annoying to get primed and started. After using them for a couple of years, I sold them and swore I'd never use Eheim again. When dirty, they barely moved any water at all. The new models seem to be very nice, but costly.
Now, my opinions:
I own four Fluvals. I like 'em. They're quiet, easy to service and keep the water clean.
I own a Jebo Odyssea CSF4, and it's an amazing product. It's huge, quiet, powerful, attractive, and very inexpensive. Although, I prefer the ribbed type hoses that Fluval uses, there's nothing wrong with the vinyl hoses it comes with. For price and performance this is my top choice!
I also have a Marineland HOT Magnum. I don't use it continuously, as I feel the other canisters do a better job as a dedicated permanent filter because of their larger capacity. It's a great filter to use for extra cleanups, though. Sometimes, I'll stir up the gravel a bit to vacuum, and the HOT is a great filter to attach a vacuum to. I think it would be fine as a permanent filter up to 50 gallons or so, and with the optional bio-wheel attachement would be great. I can hear the motor on mine though.
I've already mentioned my feelings on the Eheim Classics. The newer models I can't comment on other than price. WOW! I can't imagine the Eheim doing a better job than the Jebo does, and at about 3-4 times the cost! I know a couple of places locally to get the Jebos for about $40, and from eBay about $50-60 shipped! I don't think you can find an Eheim for that price! I know there a lot of equipment snobs not only in this hobby but every hobby. Those who believe there is an advantage to spending as much money as possible. In many cases, this is truth! But there are a lot of great inexpensive products available to us in this hobby, and the fish don't know the difference.
There are other filters that are really good, but costly and labor intensive such as Lifeguard and similar systems.