I am more biased on the DQ games but here are my votes
FF1 (DQ was the pioneer of its own so hard to compete with it)
DQ2 (Both have issues but FF2 leveling is pretty wacky)
DQ3 (Played a little FF3 on the DS but can't reach what DQ3 did for me)
DQ4 (FF4 is amazing but love the story and what DQ4 did on the NES/Famicom and love the DS remake along with the rest of DQ games)
DQ5 (FFV is great but age periods and monster party mechanics makes me enjoy DQV more
FF6 (FF6 is an SNES masterpiece but DQ6 is still gem of a game that gets overshadowed by the other DQ games)
FF7 (FF7 was groundbreaking while DQ7 was similar to the later releases and grindy and slow as well, at least the 3DS release made me enjoy it.
DQ8 (Didn't play FF8 and doesn't seem as fun as DQ8)
Can't really vote for the stuff above 9 as yet to play DQ9 or 10 or FF 10 or FF11 but picked FF9, DQ11, and FF10 for being released outside of Japan.