I have owned at least 5 SVS subs, luckily they have an excellent customer service department for the warranty as every sub I got from them (two via one of their dealers stores) failed. I took two of them apart to view the guts and I was not happy with the build quality from what I saw.
Another item, I could not get them to sound right in my large room when they were operational; the sound to me was very muddy and not musical at all; very boomy sounding.
I ended up getting in a very nice sub from Axiom Audio (who owns Bryston by the way) and all I can say is what a nice improvement that was. The amps are rated far lower in power than SVS, but trust me, they have a lot more power as they use linear power supplies with much more reserve. You should see the capacitors and massive toroid transformer; it must weigh 30 pounds. Plus they are super musical with a great amount of adjustment available on the variable phase controls and cross over points. I ended up with 4 subs from them and the sound is just outstanding. I'd suggest a look at what they offer on their webpage before getting anything from any other company; plus they have outstanding customer service and warranty support. That's my input on this subject.