I am a fan of design A and have been using it for about a year now on my current tank. Having the filter socks makes maintenance a breeze. Once ever couple of weeks simply trade them out with a second set and throw the dirty set in the washer with a little bleach. This makes it so I only have to replace the jap matt and polyfil mat about once every six months. It is also a very quiet setup. The only noise I have is from my pumps.
As far as design A being more compliated than design B, all it requires is one more piece of glass siliconed in. It shouldn't take more than five minutes longer than design B.
As far as design A being more compliated than design B, all it requires is one more piece of glass siliconed in. It shouldn't take more than five minutes longer than design B.

