Seattle has better connections to Asia, given the way planes travel it is closer to Beijing, Tokyo, Seoul than any other major American city besides anchorage.
If by "better," you mean a couple of hours shorter, then Seattle may be better.
If by "better," you mean more frequent flights, more airline choices, more destinations, and more business/first class opportunities, then New York beats Seattle with just one of its three international airports. (Four if you count Stewart.)
The difference is about 3 hours actually. And having gone through ICE at JFK and EWR, I much prefer arriving in Seattle than those two train wrecks. Not to mention getting to the airport is super easy.
