Buckeye,
Ok, one BIG thing I see between the woofers is that the Dayton and the Bully are rated at 2.83V/1m Sensitivity (or 2w/1m) and the JL is 1w/1m. (2.83v^2 = 8.009W / 4ohms = 2.002W) The JL will be easier for an amplifier to drive. So theoretically speaking, subtract 3db from the Bully and the Dayton's sensitivity numbers.
The Bully's Fs is just too high for HT. Though, it does have a lower Le than the Titanic which may make it slightly more capable for transients. JL does not have their Le published for the 15W3v2.
The JL sub also uses a slightly scaled down version of the W7's motor. In effect it is a W7 design motor behind that beast. The Dayton does have an Xmax edge, though small. I have not seen any Bl/Kms curves on the Dayton to see how linear it is. That being the case, I would have to give the JL a slight edge in linearity. The JL also offers more wiring configuration options being available in dual 2 ohm and dual 4 ohm.
i would say it is a toss up between the JL and the Dayton.