For international long haul, first class is becoming largely irrelevant on most carriers (especially United) -- a flat bed business class seat is quite good.

For domestic to NYC from SFO, consider the new flat bed seat service on Jet Blue. It's often priced at half as much as on United. For other domestic and short-haul international (like Canada), I don't see much advantage in paying a premium for F, it simply doesn't get you significantly more comfort.