Have the AT-Ms on our 2018 F150 and have had to get used to them a little as well. for some reason they don't inspire the same confidence at 50 mph in light rain that I've had with other makes. After many reviews on different forums, all universally positive, I think there is something else I'm sensing. Maybe the F150 is lighter up front than my previous vehicles, maybe the 275 width is too wide, or maybe the steering a) throws the feel OR b) reveals a subtle reduction in grip at wet roads.... IDK - but I too don't like something about how they feel on wet pavement. Acceleration-wise, they are certainly better than any used goodyear I've received with other used vehicles, and feel similar to me to upper-tier bridgestones.
The AT-M feels like a harder compound tire (UTG grading is not consistent between brands), and feels similar to bridgestones. Coopers tend to be a little softer and that might help.
The AT-Ms have stepped treadblocks which put more rubber on the road but less space between tread blocks as they wear. I won't keep mine to the wear bars. BUT, they wear like iron so I expect they will last a long time.
I'm pretty impressed - these are really large tires. 32" OEM diameter, and yet they ride like glass, exhibit no shake even after 15k miles, and needed minimal weight to balance. Signs of excellent manufacturing.
You can probably tell - I have mixed feelings and have considered replacing them too.
I read somewhere that the empty weight for my extended cab F150 is right at 4800 lbs. All things considered, that's only 400 pounds more than a 2008 Jeep Grand Cherokee 2WD. The 2.7 L engine can't weigh that much either. It may be that there just isn't that much weight over the front end, especially for tires this wide.