Most 10 and 12 inch subs of the same series made by good companies share the same motor structure. There will not be any difference in the quality of the bass assuming that each is given the correct ammount of airspace and the correct tuning in the case of a ported enclosure. The 12s have more cone area and because there are fewer of them will require less power (and the electrical support to run it) than the 10s. The only drawback I see to the 12s is that they will likely require a much larger box to work at their best. If you have room for the 10's optimal box but not the 12s', the 10s will perform better.