Apple AAPL -1.08%’s new iPhone XS (details) and iPhone XS Max (details) are now on sale and, while logic suggests users would be wise to wait for the iPhone XR (details), perhaps the best reason to upgrade has now been revealed…

‘Great Secret Features’ and ‘Nasty Surprises’ are my regular columns investigating the best features / biggest problems hidden behind the headlines.

In taking the iPhone XS and iPhone XS Max apart, teardown expert iFixit has discovered both models have an extra antenna. This not only enables support for Cat 16 Gigabit LTE but appears to be the driver behind some jaw-dropping real-world improvements to 4G performance.

Measuring 4G speeds across US carriers AT&T, T-Mobile and Verizon, popular Android and iOS signal testing app SpeedSmart has revealed both new iPhones deliver massive gains of 2-3x compared to the iPhone X under the same test conditions.

For heavy data users, this alone may be enough of a reason to upgrade. That said, it may also be a reason to avoid the iPhone XR.

The appeal of the iPhone XR is it delivers most of the major features of the iPhone XS and iPhone XS Max for a lot less money. But, if you dig deep into the XR’s specifications, you’ll see that it compromises by using the same Cat 12 LTE connectivity as the iPhone X. And we now know that’s a world apart from its more expensive stablemates.

Of course, the iPhone XR does have one equally appealing advantage (besides cost) over the iPhone XS Max and, in particular, the iPhone XS and that’s much better battery life.

Consequently, while news of the flagship models’ 4G performance is very welcome, it makes me wonder why Apple failed to release one new iPhone which has it all…