At regular price, probably not, but at the sale price of $189, the JBL550p is probably at least twice as good, since two would cost less than a single SB12. The JBL is a 10" but I'd be very surprised if it isn't at least as capable if not more so than the SVS.
For a larger, more powerful sub, Hsu's VTF3 MK5 is the best value under $1k....I'd take one over dual PB12's. I demo'd the PB12NSD, returned for the PB2000 (was released a week later) which is the same thing with a couple dB more output, and returned it too when I realized it had mediocre mid and upper bass output. It hit its limits very clean and unobtrusively, but moving up to a more capable sub was drastically noticeable at spirited levels.