Originally Posted by BOSTransplant

I think you would be best served sticking with AA, at least for one more year. Delta's rollover MQMs only kick in above the first tier (25k MQMs for silver), so if you don't hit that, then you won't get any benefit from that. Additionally, if your top priority is traveling with the family for free, then right now AA's ffp is more valuable. They've already started shifting towards the DL/UA model with their changes for next year, and I wouldn't be surprised to see them continue to devalue going to 2017 onward, but for 2016, AA will still have a more valuable program than DL and UA. It'll be especially good for you next year, since you've managed to hit plat.

Another thing to note is that even if you hit silver on Delta, you will rarely be upgraded flying out of LGA/JFK. I've heard that some of the smaller, regional flights out of those airports aren't too bad on the upgrade list, but if you're flying somewhere like the west coast, Atlanta, or Chicago, then you have virtually no chance of being upgraded as silver. As painful as it is, your best upgrade shot is slowly accumulating 500 mile stickers with AA and then cashing them in.

As for your last point, I actually agree that Delta's hard product is better. Better planes, better operational service, etc. I'm just not sure that you travel enough to make that benefit counteract the decrease in frequent flyer rewards that you'll experience. If you think you'll have a significant uptick in travel in the future, then maybe you could consider preemptively swapping to Delta to start building lifetime rewards, but otherwise I would say enjoy your AA plat status in 2016 and revisit this question next year if/when AA announces big program changes for 2017 and your status drops back down.