100% of my flights from Europe to the SF are A) and 100% of my flights from the SF to Europe are B). Quite frankly the deciding factor here is that the factor that outweighs everything is that transferring at a European airport is speedy, luggage stays checked and I don't need to go through security. Transferring in most of the US from an international to a regional flight is a much more involved undertaking.
The same kind of thinking for me applies to a lot of public transport too. I pick based on how annoying transferring is.
But you are also in SF, so you are already at a Hub of sorts that is well connected and is going to get you at least to a close by airport in Europe. If you were living in Seattle which is less connected to Europe than SF, you would be doing B more often.
In scheduling a trip from Seattle to Tokyo, direct in the way there (as it should be!) but on the way back I have to transfer in Minneapolis. I don’t think I could have flown to Osaka or something to get direct at a reasonable price.
Do you have Global Entry? It’s open to citizens of many countries and you can feasible get off the plane and be going through security (past immigration) in under 10 minutes. I wish other countries offered a Global Entry experience.
I think programs like Global Entry are one of the main reasons American airports are usually so bad. When most frequent flyers can avoid the default experience, nobody really cares about fixing it. In a well-run airport, everyone gets an experience similar to Global Entry by default.
most other countries have a customs/security process that is as fast as global entry. So everyone gets a good treatment most of the times. It's not pay for convenience, its a fair treatment for all. I honestly think global entry is a backwards solution to the problem, and only makes it worse for non paying people
Other countries have a more straightforward entrance protocol, I've never been stuck too long (I mean, except in case of strikes) in a customs queue in Europe
The same kind of thinking for me applies to a lot of public transport too. I pick based on how annoying transferring is.