There are a lot of JL's units for sale on AG probably because they have become a leader in subs, look how many Velo's are for sale on AG...
Revel Sub 30 vs JL Audio F113?
Looking for a pair of subs my Ultima Gems, obviously the Sub 30 has the advantage of being designed to work with the Gem and has a built in crossover, it nice that it matches aesthetically as well, but I have heard great things about the Jl's. Anyone have experience with these two subs?