Which class are you going to take? If Y, nothing can beat SQ's 773ER product between SFO and ICN, seriously. The problem is SQ's economy class is super expensive if you want to get miles from your trip - SQ usually release only Q (no-mileage) class for budget travelers which is quite cheap - around 1000 USD for SFO-ICN return. Currently airfares are extremely high - cheap ones will come out around Feb/Mar. Asiana product is much better than US, so if you can purchase OZ to TPE and make a stopover ICN, it will be great, but usual OZ ticket to Asia does not allow stopover at ICN unless ticket is quite expensive. You need to buy through travel agency to get cheap OZ ticket, in usual. UA and AC also offer somewhat cheap tickets to Korea. UA's coach class is similar to US air's, but AC is said to be much better than UA/US.