List the existing and upcoming games exclusive to each platform, which you want to play. Then buy whichever one wins out in terms of quality and quantity.
That the PS Vita has the least games is irrelevant, if it turns out it has the most titles you really want to play. That the 3DS is region locked won't matter if you buy one from the region where the games you want get released.
That the PS Vita has the least games is irrelevant, if it turns out it has the most titles you really want to play. That the 3DS is region locked won't matter if you buy one from the region where the games you want get released.