What is the forums opinion of SVS subs?

I have an SVS and a B&W. Love the SVS much cleaner than the B&W, deeper bass and great value for the money. Overall great sub! Good luck with your pick.

@ratboysr, I may be wrong but I get the impression you think it necessary to have all subs in a multi-sub set up exactly same model. You are free to use a different type and in fact may prove beneficial. For example when helping a friend with 3 subs, 2 of them 10" and 3rd 12" my measurement showed a stubborn partial null at about 70Hz. Floor space was a bit lacking so I brought over a 6.5" little sub in a 9" sealed cube. After some experimentation found it worked wonders placed about 4ft off the floor on a large bookshelf.  Measurement confirmed the the null had improved from -10dB to -4db.  The small sub was about 5ft away at almost ear height so would not need much power but received enough to further smooth out the room response. In fact when turning up the volume on this sub I could fill in that 70Hz completely but raised a nearby peak a couple of dB. I erred on the side of caution to protect the 6.5' driver.

Generally it is best, for easier integration, to stay with sealed boxes. Multi - subs are transformative and I am constantly surprised by the reluctance to accept/ embrace the concept.

If you are considering the SVS line another brand that gets little attention but are as good or better than SVS is Arendal Sound for the same money. The 1723 series subs are very good. 

My experience is with a Plus and an Ultra, both 8-10 years old:

The main issue was the volume control, which blasted when barely cracked. I trained many different methods to employ them, to no avail. I had them with 3 different speakers. It took years of advertising them FS until someone bought them for his Video system, which is what the company originally was based on. So, if you're looking to use them in a  channel system ask before you buy

hth

SVS makes really good subs and they have great customer service and they are reliable.  I have 3 of them, one SB-12 NSD in a bedroom system and two SB-13 Ultras in my main system, combined with two Rythmik F25 subs. 

I have heard Rel subs and think they are great, but I have a hard time justifying the price difference between Rel and many other brands.  There isn't enough sound "difference" IMHO to pay twice as much or more for the same level of output/performance.  

I'm scratching my head a bit about the comment about them being too loud.  The two in my main system have the volume set at something like -14 and -15.  When I bought my Rythmik subs, I bought them pre-owned.  The owner said something like "I have them set neutral" which in his mind meant that he had his AVR set at 0, but I don't think they were in any way calibrated or "neutral".  They were overwhelming.  You probably could have heard them half a block away the way he had them set up.  In my setup, the volume is at about 9 o'clock. 

Having them set up so that the volume control can be set low is a good thing.  That means that when called on, they will respond with ease and have lots of overhead and when they are not a prominent part of the musical content you may not even realize they are there, when properly integrated.

Having lots of overhead is generally not considered a bad thing when discussing subwoofers.  Some subs can be too big for the space, which is why there are multiple models in every sub manufacturer's lineup.  

If a sub isn't good for music, it's not going to be good for home theater either and vice versa.  I do however prefer to stick to sealed models for music.

Before you purchase either a Rel or SVS, I would suggest looking at Rythmik.  I like their servo technology and would recommend them over SVS and you'll get more value for your dollar than you will with Rel.