Xs Max on iOS 12.0.1
512 GB
Silver
AT&T through Apple.com preorder
F2XL9... SERIAL
ZHENGZHOU
2nd half of 2018
9TH week 8/26-9/1
LTE fine, same as my other iPhones
Clarifications:
LTE - Decent service and performance vs our Qualcomm iPhone X and 7 on AT&T, and much better than our iPhone 6 on Ting.com Mobile. Our Cheyenne Mountain neighborhood has notoriously poor cell service on LTE, and we get 1 bar with AT&T or Ting (I think it's an MVNO on T-Mo, costs me $6/mo if I don't use the spare phone).
The Xs Max runs typically about 1-2 mbps at the house with 1 bar LTE, just like all our previous AT&T iPhones having 1 bar LTE (the 6 on Ting has 1 bar). But I got 30-50 mbps with the Xs Max in downtown Colorado Springs, and 80-90 mbps in Denver. With a decent signal my iPhone X is usually about 60-80% as fast as the Xs.
Here at home right now as I type, the Xs Max on AT&T gave me 1.47 down / 0.40 up, and my X ran 1.70 down / 0.01 up. However, the iPhone 6 on Ting.com wireless LTE just ran 0.15 down / 0.07 up. Proof my neighborhood LTE sucks.
My Xs will drop to 4G more easily when the LTE signal gets too low, while my X tends to hand onto 1 bar of LTE even when the data speeds would be slower than 4G. That's why I usually just turn off LTE on the X when I get home, in case I take it with me on a walk without WiFi.
WiFi - after the 12.0.1 update, WiFi on 2.4/5.0 Ghz Time Capsule jumped from 25-30mbps to now 180-200 mbps, like the X, while the iPhone 6 is consistently at 25-30 mbps on the time capsule.