probably get more head-room and punch at high volumes with the JL subs. I sold Rel in past, which are very musical subs - Not so much slam and power with HT rocking, though.
Personally, I like the combo of musicality and HT slam factor of the Paradigm Servo 15 for cheep money, in a large room. The Earthquakes also fill a huge space, take lots of power, and are pretty tight when setup correctly.
As with ANY sub, however, your main issues are getting the subs set up in the room properly, in relation to the seats and speakers. Get phase wrong, or sit where there's big suck out in the bass, big bass humps and imporperly mated coherence with the mains and it is all a moot point! You'll never have great bass performance...just a big sonic mess of over-bloated bass engery, that's got lots of issues, and negatives, rather than fast, tight, dynamic, extended, coherent bass with slam and seemless integration.
I'd say 3/5ths of the performance is acoustics and setup with the sub (EQ'ing?), and the rest is design of the sub itself. That's bass for you....