I kept a standard 29gal for many years in my early teens(15+ yrs) ago. Ounce I got into cars and girls(as most 16 yr old males do) I gave it up. Well I just started up a custom made 24"x20"x20" aquarium and am on a tight budget. I could find almost nothing on the the PennPlax external canisters but took the gamble because I could get the filter capacity and features of the cheapest model that was $20 more. One complaint I often read about Rena was noise. To get a Fluval that could handle more than 40 gal was a little pricey.
Here's my experience so far.
This thing is SILENT. I haven't made the door for the cabinent I built (yes, I finished all but that and wanted to get water in the tank). You have to sit on the floor in front of it to know its even running. Once the door is built tomorrow, I won't hear a thing. My only complaint is that I wish the hose couplings were a little sturdier or the system was altered for some type of quick couple setup. It also pulls a little more electricity than some of the others (25w rating on the motor), however, they rate this thing for tanks up to 60 gal, thats not too bad. I am having to slightly restrict the flow because its too strong for the types of fish (Platies and Mollies) that are in the tank at the moment.