Kicker is still (by a large percentage) the most successful subs in nearly every car audio competition organization.
As much as I find the square sub idea to be gimmicky, they have even been largely successful in SQ competition. I would be willing to bet that they have had no noticeable change in return rates in recent years.
I do agree that an W7 is a tremendously better sub than an L7, but in terms of loudness, the L7 would be all over a W3. Personally, I would prefer the W3 in most cases if I were competing for SQ, there are instances where the L7 would be a better choice. For instance, if I were going with a free air sub, the L7 makes a much better choice than the W3.