San Diego is 120 miles from LAX, and every public option involves at least two changes with luggage: FlyAway or rideshare to Union Station, Amtrak Surfliner south, then a taxi at the other end — four hours if the connections cooperate. A private transfer is one car, one driver, door to door in roughly 2 to 2.5 hours.
The fare is fixed at $425 per sedan and $600 per large van — for families and groups it's competitive with four Surfliner tickets plus both taxi legs, without the platform sprints. Rest stops on request, child seats installed, and the Carlsbad/Encinitas/Del Mar coast is on the way if you're staying north.
We also run San Diego from John Wayne ($325) and Anaheim ($350) — the classic Disneyland-then-San-Diego family itinerary in one booked ride.