I don't know about JL room correction, but I used to own a Martin Logan sub, got the mic and software - total waste of time.
Sold it and bought 2 REL T/9x's and never looked back - I run them from RCA sub-outs with 80Hz pass from the amp and use the LFE inputs from my AVR sub-outs.
Easy integration, sound great. I think SVS is a good choice as well.