The answer to this question may come down to personal opinion,
because these two pilots are not only in completely different
mobile suits, but also in completely separate universes due to
belonging to a respective series. I, along with most other Gundam
fans, would agree that Amuro is a better pilot. Having more
experience due to being a Newtype Gundam pilot since the age of
fifteen, combined with the sheer speed, power, and the
Psycommu-driven cockpit of the fin-funnel powered Hi-Nu, would
assure Amuro's victory. All in all, it's an interesting subject!
Perhaps we'll see this fight some day in a Gundam mash-up similar
to Gundam Musou (Dynasty Warriors: Gundam).