About a year ago I set up a 120g tank for my oscar using twin HOB Penguin 350s. They were not adequate filtration for that large of a tank but it was all I could afford at the time. I had to modify the filters to fit the large lip of the tank and when the water started to get a little low they it began to sound like a waterfall in the livingroom.
I found a deal on ebay for a new Fluval FX5 which is what I had been looking at at my LFS where they wanted $400. The ebay pet store was buy it now for under $250 and I couldn't pass it up.
When I got the filter the first thing I thought when I opened it was "holy crap this thing is huge". I was actually worried it wouldn't fit under my aquarium because of my split cabinet.
The filter actually came with a DVD to help set it up and it was very straight forward and simple. There are some minor modifications that you have to make to fit it to your aquarium such as cutting hoses and such, but anyone with two hands should be able to set it up.
Now here is the best part of the whole deal. After listening to the noisy HOB filters for months, waterfall sounds and impellors rattling, I was hoping this filter wouldn't be any louder. I plugged it in and after it clears all the air from it's system it was almost completely silent. I have to turn the TV off get down by the aquarium stand and listen to hear it!
The filter actually shuts itself off for a few minutes every 24 hours to allow any accumulated gases to be expelled when it starts back up. Pretty fancy for an aquarium filter.
If there is a downside to the filter it is cleaning it. With it being the size of a 5 gallon bucket it is quite large to wrestle around. Cleaning requires you to remove the outflow tube from the filter and replace it with an extra one to pump the filter water into a bucket to empty it (there are valves to cut water on the inflow and outflow tubes but there is no way to keep a small amount from spilling during this step so have a towel handy). Once the filter is empty you can undo all the clamp screws and pull out the 3 trays and filter pads. Once filters are rinsed and carbon and pads are changed you reverse the process and hook everything back up.
It is not something I do very week but not as bad as it sounds. Personally it is a small price to pay for such a quiet powerful filter and I am thinging of adding another one to my 120g even though it is probably overkill.
In the end I highly recommend this product to anyone with a larger tank and/or messy fish. My oscars (yeah I bought another one) love playing in the outflow (which is intensly strong) and I would buy another one in a heartbeat. Deals can be had on ebay and I recomment using the Fluval polishing pad as it made my always murky water, crystal clear.
I am not affiliated with Fluval in any way other than being a extremely happy customer.