can subwoofers make things worse?

YES.  Other than truck/car audio and HT the money spent on subs could be added to a speaker budget and if one's strapped for cash there's plenty of used, floor standing active speakers out there that will deliver the goods and take less floor space.

@sudnh Note he did not say SVS was a one-note boom sub and said it was capable of doing bass tonality.  In general are they as good as REL or Rythmik in that area, no.  But neither are they a one-note boom box as you imply.  That he lumps JL Audio in the same camp as SVS seems pretty silly BTW.  And it’s also ridiculous to imply if a sub is musical it can’t slam.  I’ve heard Rhythmik subs and they sure as hell can slam, so that’s just total BS — a good sub can do both musicality and slam and they are not mutually exclusive.  Of course it’s all about integration, and a well-integrated SVS sub can sound great and certainly not a one-dimensional boom box.  I can point to ten other reviews where experienced reviewers got great results for music with SVS subs, and not one of them categorized them as one-note boom boxes.  This reviewer didn’t say that either — he was just over generalizing to make a point.  Your assertion that SVS is all about boom is misguided and misleading, and there’s plenty of evidence in the form of other reviews to back that up.  I have an SB2000 and it is NOT just a boom boom sub if properly integrated.  Is it state of the art?  No, of course not, but it’s not what you call it either.

That video was interesting and captured the fundamental difference in subwoofer approaches.  While I generally avoid subwoofers, I have helped with installations using them and I agree that REL is good at integrating the woofer with the main system (both effective and easy to accomplish). 
I have also heard SWARM subwoofers integrate well (not surprising because they employ many subwoofers to distribute room nodes).

@larryi 

+1

@epz As you can see the HiFi community disagrees on subwoofers, choice and implementation which can easily lead the worse. Start with manufacturers that offer a simply return policy and customer setup phone support.  

When I put a $9K REL in my room the first thing I noticed is that its not really a subwoofer. In its manual titled Sub-Bass System the claimed a frequency response is -6dB@9Hz. Our best in room measurement began to roll off in the mid 30's, at a barely audible -6dB was 27Hz. Compared to the other subs in the room the big Brit's integration was the worst. So much for direct in room comparisons.

Even though I swear by my subs DSP, remote control and EQ presets. I prefer to use as little as possible which made corner placement out of the question in every room they've been in. Playing a low frequency test tone with a sub in the listening position to locate the rooms bass modes are where my two subs are positioned. 

A little hassle at first but when you get right you'll never go back.

@sudnh , Many times, the 1 note boom is because you're seated right on top of a room modal peak. Other times, the perception of a 1ish note boom can come from ported subs and associated group delays. The big SVS ported subs have appeal for the boominaughty hometheater dudes when they're watching Godzilla or some fratty maverick shooting things (SVS's primary market). A SVS sealed sub integrated correctly won't give you 1 note boom.

P..S. That neck bearded reviewer on the vid though...he kinda looks/ sounds like a 1 note boom, 

That neck bearded reviewer on the vid though...he kinda looks/ sounds like a 1 note boom

@deep_333 Heh heh.  Good points BTW.