i have ran 13w7's. I liked them, but then again i got them for less than 500 each.....with about 5 hours or so on them when i bought them. I would not pay the price they want for retail. FYI, i had two eclipse(tc sounds) twelves in my truck that got just as loud and sounded just as good as my JL setup. I say sound quality was around the same, but others say it was better withe twelves.
I have heard some of the refrence series mb quarts twelves and they sound awesome and are relatively cheap, and get LOUD. They are the ones with the inverted surround, next time i am at my buddies house i need to remember the vids.
Other brands that i have heard with great SQ are SI MAG, and some type x's, but there are many videos and tests on the web that test and compare all kinds of woofers.....I have been dying to try one of the Crystal Comps in the wifes car...
jason