Interesting^.
Anyway, I recommended him the RL-p first because compared to the JL and Hertz, it is every bit as good for not as much money. I've heard W7s, W6s and my RL-p. I prefer the sound of the RL-p and W6 over the W7, but the W7 was loudest (all 12" enclosures, heard my sub ported and sealed, and I've heard both JL subs ported and sealed).
Not may people on here have experience with the Hertz Mille subs, but they look awesome on paper and knowing Hertz quality. With the price he was quoted for them, I suggested he try out the Hertz subs, but like it has been said, I don't think he could go wrong with any of the choices.