Personal preference is the JL's. The power rating on the JL is very conservative. I also know that the JL's have a much lower failure rate than the kickers.
JL Audio is a lot better than Kicker and Kicker is really good, so that should say something. Although the JLs have less xmax than the Kickers, but the SQ is a lot better. If you want SQ I'd go with the JLs, if you want SPL I wouldn't go with either of the subs. For SPL I'd go with Sundown Audio, Digital Design, Orion, or Fi. Good luck!