if you have the space get the atlases I don't so I will be getting W3's XBL^2 is supposed to sound great. I just can't fit them //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif
Don't have both to do a direct comparison. I would expect XBL^2 to win for SQ from what I have read. and possibly win for SPL so you would have a good SQL setup. Neither sub is an spl champ. From what I remember on another forum people were recomending the Atlases over W3's.
I owuld not hesitate to get an Atlas except that it won't fit, the W3's have less mounting dpeth and top vented VC's so you can mount the magents very close to the rear wall in the enclosure.