spl or sq?

I definitely prefer SQ, mostly because even SQ systems can get PLENTY loud enough for my listening tastes.   I don't see many real-world applications of SPL, because when you're talking 150 dBs or whatever, that's already beyond the threshold of pain and easily past any volume you would ever want to listen to on a regular basis.

SQ on the other hand has more potential for real-world applications, as its volumes are more in line with what people might want to listen to every day in their vehicles;  also, it can apply to music and not just test tones.

That's all just my opinion, but really the two cannot be compared because as big purds said, it's apples and oranges, and everyone is going to have their own opinion.  Certainly I respect anyone who competes and is successful in either category as it does entail a lot of work and not just anyone with $20k to blow could build a competition vehicle.  There is a lot of talent in both areas.  Ultimately though in my book SQ gets the nod.