The HTC U Ultra is 6-percent taller, 7-percent wider and 8-percent thicker than the OnePlus 3T.
The Ultra is also 8-percent heavier.
HTC went with that Samsung-esque build (it looks almost exactly like a clone of the Korean company's 2015-16 flagships), with glass back and aluminum frame. OnePlus uses an aluminum unibody design.
While there is technically a gold version of the OnePlus 3T, it's out of stock – leaving current buyers with one (gunmetal) color option.
The HTC U Ultra has a 7-percent bigger display.
One of the few cost-cutting corners OnePlus took on the 3 and 3T is their 1080p display. But while 1440p screens, like those on the U Ultra, deliver an extra dose of eye candy, 1080p is plenty sharp for all but the most discerning eyeballs.
It's the old IPS vs. AMOLED, though HTC is using the Super LCD 5 variant, which eliminates the air gap between glass and display.
HTC photocopied a page from LG's playbook with its second screen. The small strip, sitting just above the main screen, is home to notifications and shortcuts.
While the Snapdragon 821 is a speed demon, it's going to be dated by the time the U Ultra finally launches.
OnePlus has one-third more RAM.
HTC only offers one storage tier, but it's a generous 64 GB – the same as OnePlus' base tier.
You can also expand on the Ultra's internal storage with a microSD card.
This is potentially a reason to balk at the Ultra: Despite needing to drive more pixels on its display, it has a 12-percent smaller (lower-capacity) battery. Consider this a yellow flag until we put a review unit through battery tests.
Camera aperture (rear)
The U Ultra does have a wider aperture, often a good indicator of superior low-light photography.
Both phones include Optical Image Stabilization.
There's no meaningful water resistance in either phone; you'll want to look to a 2016 iPhone (good) or Samsung flagship (better) for high-quality water protection.
Neither phone supports CDMA networks: U.S. buyers are limited to AT&T and T-Mobile, with no Verizon or Sprint support.
Each handset has a home-button fingerprint sensor.
HTC says the U Ultra will launch with Android Nougat, an update that OnePlus only recently pushed to the 3T.
The OnePlus 3T runs (more or less) stock Android, though, while HTC put its own custom UI on top of Google's core OS.
So much for instant gratification: HTC announced the U Ultra two months before it's scheduled to start shipping.
The OnePlus 3T launched in November, but it's a minor iteration on the OnePlus 3, which started shipping last June.
Starting price (full retail)
This is the OnePlus 3T's killer feature – and another big reason to balk at the HTC U Ultra. With a concerning battery size, soon-to-be-outdated processor and two-month wait to get your hands on one, HTC's new phone is probably not your best buy right now. Stay tuned, though, as we'll have a review around launch.
For more on the best smartphone value today, you can check out New Atlas' OnePlus 3T review.