neithers better cause everyone is different. if you want just really loud bass but don't care to much how it sounds then spl is for you. if you want it to get loud but still sound great go for sq. best thing to try for is a system that gets really loud and still has great sound which is sql.
some people might disagree, and i know i'm far from the smartest on this forum, but i don't honestly think kicker can really be much more than spl. the cvx's will definately sound better then the solobarics, but they still lack the sq of others, like jl or aa or others. but if you want it loud it'll definately be good for you just be sure to have really nice speakers in the front so as not to drown everything out with the bass. i'd recommend a really nice set of components and decent rear speakers and properly power them.