More appropriately - the evil water heater. You must be speaking of the small cylinders.
. You are correct - personal preference is bosss (unless overruled by the wife).
Once you get past style, there is really only one consideration are you getting enough equpment to have it act like a subwoofer, or did you get almost enough equipment and you have a subwhimper. If there is a compromise because of funds to go to subwhimper, don't buy one - you wil be disappointed forevermore.
The question is a good one, it's just being asked in the wrong place. You need to talk to Axiom, SVS and (for the HSU train that is about to pull in), HSU Research. They will guide you, based on room dimensions and a variety of other things, to the correct choice. Not one of them will oversell you. If budget and capability don't cross paths, delay until you save enough.
BTW - there is nothing wrong with hiding the sub behind a piece of furniture I've got the "evil water heater" behind a Lazy Boy (double that if I am sitting in it) and no one knows its there.
