THIS! I'm on Cricket (AT&T towers) and I'm sometimes disappointed with reception. I'm assuming this will improve things. I also know that the 8 did not have T-Mobile Band 71 (600 MHz) - they will also get a signal improvement. It's what's inside that counts the most...This is something that I think many people are overlooking, and even this author kind of glossed over by simply saying that the new bands would only help international service.
For anybody who has an iPhone 8/X or older, you’re missing band 14 which is a huge part of AT&T’s low-band LTE capacity. That’s the “FirstNet” band — that’s the 700 MHz band that’s going to get you improved in-building coverage. And it’s available for all customers to use, not just FirstNet subscribers. Not to mention that the XS and newer support 4- or 5-carrier aggregation. Anybody who doesn't have an iPhone XS, XR, 11/11 Pro, or this new SE is missing out on a lot of speed and coverage.
Likewise, with T-Mobile, band 71 is equally important for the same reasons. I understand that the iPhone 6s and 7 look similar by design, but the improvements in LTE bands and CA make a huge difference for coverage and capacity, which actually helps out everyone by spreading data load across more spectrum. And that’s a huge part of the value of upgrading 2+ year old iPhones that’s really not being discussed here.