Go with the cheapest - extra cash in pocket is the safest. You may not need extra luggage allowance. You can buy lounge passes at some LAX lounges if you need to. Seat choice is good but they likely to sit all four of you together anyway. Priority check in is not a big thing if you have time. Your priority is different from many of the FFs who fly every week on tight schedule and alone (and may need to work in lounge or on flight).
You cannot predict the crew you get on a particular plane or flight delay or what people sit around you etc etc. save the money first - it is the only guaranteed advantage.
You cannot predict the crew you get on a particular plane or flight delay or what people sit around you etc etc. save the money first - it is the only guaranteed advantage.