Personally, I would upgrade. It's a kinda "once in a lifetime" thing (if you travel on the cheap normally), on a cross-country flight. If you can afford it as a one time thing, totally do it.
We've had the fortune of getting fairly decent deals on first class a couple times. It was worth the meal and the t.v. + 2 free checked bags each. Would we do it again? Probably not, just because the thrill has worn off and we try to budget for other things (like taking more frequent vacations). But then again, we haven't done flights longer than 3 or so hours.
BTW...we were shocked at how simple LAX was. Everyone makes it out to be some huge hassle and that they absolutely hate it and they would never travel through it again. Security was a breeze, getting from/to the terminals was easy. We thought we were getting away with something with house simple it was. Granted, we didn't have checked luggage that trip so it may have been different.