I take a Lyft/Uber from SNA. Usually 15-45 minutes depending on traffic. Agree around $30-40 before tip. I'm flying into SNA on Tuesday, fingers crossed!
The LAX rideshare situation isn't awful. I like the new LAXit area, easy to find your driver. Terminal 1-3 isn't a far walk, maybe 10 minutes tops in a straight line. Not bad if you only have two roller bags per person, would be hard if you had more than that. I think Southwest is Terminal 1, Delta is 2-3. I think the higher terminals are further and you probably want to hop on the shuttle at that point. I've usually spent around $200 round trip, the airport pickup is usually a lot more expensive than the ride back to the airport due to fees.