Take this with a grain of salt, because I've only flown into and out of there on a connecting flight, and that was 10 years ago. The flight was....memorable, to say the least. We left Seattle in November, dressed accordingly, with our toddler, baby in a stroller, and car seats for both. Had a quick connection several terminals away. They don't have a nice tram, like most other multiple terminal airports I've been too...their website says they have a shuttle, although when we flew in we were told that we just needed to walk to get to the next terminal. (Staff was not at all helpful). Needless to say...dressed for winter, in summer like conditions, with 2 littles and loaded down...that was the longest walk of our lives. To this day, I think LAX is probably the worst domestic airport we've flown into or out of (although Heathrow was definitely worse, and San Francisco is far scarier- steep descent landing!!!). That said...we don't choose airports for their ease, we choose it for it's convenience towards where we go and/or price. In this case, we'll be flying into LAX this summer because of cost (even a $50 difference adds up when there are 4 of you), although the OC airport is closer to
Disneyland. So...if I were making a pro/con chart: OC is closer (if you're headed to DL, rather than somewhere else first) and a smaller airport. LAX will offer you more flights especially if you are flying out of a smaller airport, or have specific airlines you want to choose or to avoid, and it will save you money. For us, in this case, flight times and cost are the 2 big considerations.
I can't speak to traffic in or out of the airport- will you be driving, or taking some other transportation? Looking at them both, It definitely looks like OC would be friendlier to drive out of, if that's a factor (and if you are driving, your comfort in driving in big cities) If you're taking a shuttle, it would be slightly cheaper from OC to Disneyland, but not as much as the price difference for flights...