The HTC One packs a 2300mAh nonremovable battery. In my experience, the battery has been good but not bulletproof. On days where I had low to moderate levels of usage -- what typical smartphone users would probably consider normal -- I made it through with plenty of charge to spare.
On days with heavier use, though -- 30 minutes of video streaming, an hour of audio streaming and a couple hours of scattered Web browsing and social media activity, for example -- I started seeing low battery warnings toward the end of the evening.
What about data connectivity? The One supports both LTE and HSPA+ networks. For AT&T and T-Mobile users, that means the phone will connect to LTE by default,then automatically drop down to HSPA+ if you're in an area where LTE isn't available.
Given the fact that HSPA+ data speeds are often equal to or even greater than LTE speeds, this is a meaningful advantage -- particularly when compared to Sprint, where LTE connectivity is still rare and painfully slow 3G service is the only alternative.
I found voice call quality on the HTC One unit I tested -- which was a Sprint-connected model -- to be perfectly fine; I could hear people loud and clear and those with whom I spoke reported being able to hear my voice without any crackling or distortion. HTC says the One has several call-enhancing features, like ambient noise detection and dynamic volume adjustment, but I was unable to detect any noticeable increase in quality based on their presence.
The HTC One supports near-field communication (NFC) for wireless payments and data transfers. It does not, however, support wireless charging.
By now, you've probably heard about the HTC One's unconventional approach to smartphone imaging. In short, while most manufacturers brag about a large megapixel count for their smartphone cameras, HTC has opted to go with fewer but larger megapixels on the One -- a change the company says results in better real-world performance for the types of pictures most people take.
The HTC One's camera uses 4 megapixels -- "UltraPixels," as HTC calls them. According to HTC, that configuration allows for 300% more light to be captured than what you'd get with a typical 13-megapixel smartphone shooter.
The One features a bunch of other fancy-sounding camera technology, like a dedicated image processing chip, an f/2.0 aperture and a high-frequency optical image stabilization system. In my real-world tests of the device, all that stuff added up to pretty solid performance.
The One's most impressive images seem to be those captured in low-light environments.