depends what your looking for..they are all cheap(pricewise) but their all good SPL Kicker>Alpine>Infinity SQ Infinity>Alpine>Kicker as you can see the infinity is the best sounding sub, the kicker is the loudest and the alpine is the in between one
well if it was me i'd take the kicker but thats what i like, quick shot has them in the right order for spl and sq but listen to all them for yourself then decide, but were are u getting ur subs at because every i've looked the kicker is cheaper than the alpine.