I would book the ANA flight.

1. There are enormous benefits to not having to go through US inbound immigration in a different city than your final destination. You avoid having to claim and re-check bags, having to go through domestic security, and risking missing the US domestic flight. SFO is also notorious for delays if the weather isn't perfect.
2. The ANA cradle seats (I assume it's a 767?) are perfectly serviceable for a day-time intra-Asia flight. They don't lie flat, but they do recline pretty far, enough that it's quite comfortable for relaxing and napping (much better than a US domestic first class seat). Plus, if you take the CI flight, you'll have to deal with a recliner on UA's SFO-SEA flight, and that will be much less comfortable than the ANA 767 recliner.
3. NH feels like a more operationally competent airline than CI.