LAX TBIT = a total hole to arrive in. Avoid at all costs if possible. Definitely arrive in SFO.

On departure, I have yet to try the new lounges at LAX which have good reports on FT. The SFO lounge, however, is a nice (old-style) Terraces with separate First room. And best of all you all board from the lounge itself. Departing SFO should be as stress free as arriving, but the lounges themselves at LAX might just be a notch better. Regardless, I would opt to both arrive and depart SFO over LAX.