SVS to JL Audio

JL Fathoms and SVS are both fantastic subs - I've owned both.  They are both extremely impressive, especially for their size.  I don't think you'd find one to outperform the other to a significant degree where 'tighter / more articulate bass' is concerned.  Depending on your room, there my be significant gains to be had with things like sub location, treatments, or DSP.  
Focusing only on the speaker, one sub that I have found to outperform both the Fathom and SVS subs is the Seaton Sound line.  I'm running the F2 now and find it to be the best sub I've ever owned - hands down.

Im trying to decide between sb13u, F110 and e112. Curious if you ever made decision on this. Is there something lacking in the dual sb13?

A good comparison---both excellent subs. Another in their class is the Rythmik F15HP, which HAS been compared to the SB13 Ultra. I don't recall where I saw the comparison, but of course a Google search will bring it up