I called JL Audio when I was shopping. The techs said for their own systems, they prefer two f-112's over a single F-113. They felt the detail was better reproduced. Makes perfectly good sense, too. Both are certainly great reference, statement quality subs.
I have and enjoy a SVS Ultra 13 very much for both music and HT. My top choice would have been two F-112's or possibly two F-113's. i'd have to look over stats and subjective reviews closer again.
Consider one and add another later. Expensive and reference quality, yes. This level of gear should not beg for replacement anytime soon.