Samsung’s new Galaxy S10 phones feel great to hold and to use, and you can pick from a library of features to explain why that is. Having handled all three of the new S10s unveiled today, I’d say my favorite thing about them is the new in-display, ultrasonic fingerprint sensor. It lets Samsung combine the gorgeous all-display screen with a clean design on the rear and the convenience of fingerprint authentication on the front of the device.

Built into the Galaxy S10 and Galaxy S10 Plus — but not the lower-tier S10E, which makes do with a fingerprint scanner embedded in the power button on its side — Samsung’s ultrasonic reader is easily the best in-display system I’ve tried yet. Vivo was first out of the gate with an optical solution at this time last year, but it was pretty slow. Then Huawei, OnePlus, Xiaomi, and a variety of others followed, but they were all substantially slower and less accurate than the capacitive fingerprint readers we’d all grown used to in the past. Over the course of 2018, I’d say I rather soured on the concept I originally found delightful, because all the implementations were underwhelming and frustrating.

(My colleague Sam Byford assures me that optical in-display fingerprint sensors have gotten much better in the Vivo Nex Dual Display, and I believe it, but I haven’t yet tried that out for myself.)

Samsung isn’t first with the technology, but it’s definitely among the best

Samsung has set everything right about in-display fingerprint readers with its S10 devices. The most important thing is that the responsibility for accuracy should be born by the phone, not the user — I shouldn’t have to precisely place my entire thumb on a tiny window that can read and identify a print. With the S10, I can be as sloppy as I like with my finger placement in the lower third of the screen and it authenticates me without a problem. I can just feather the surface of the phone, and it still recognizes me.

The most surprising and delightful thing about the unlocking process, though, is that Samsung has designed a beautiful transition for it. I can use the fingerprint sensor even when the screen is off, but the Galaxy S10 doesn’t instantaneously go from black to the home screen: the display turns on gradually, with an organic quality about it that somehow makes the unlocking process a little magical. Yes, I’m conscious that I’m praising a delay in the unlocking of a phone as a good thing, but when that delay is consistent and reliable, it becomes a good pacing habit; it gives me a moment to remember why I was pulling the phone out of my pocket in the first place.

One concern that was raised by a pre-event leak was the idea that the new fingerprint sensor tech would require screen protectors for the S10 devices to have an unsightly hole in the middle. Previous ultrasonic systems of this kind have been able to get through thin covering layers on top of the screen, but Samsung tells me that tempered-glass screen protectors wouldn’t be compatible. You should still be able to use thinner plastic varieties, though. This will be something I’ll try to get more information about from the company.

You’ll often read or hear discussion of how Apple doesn’t care to do things first, it cares to do them best. Well, Samsung wanted to be first with this technology, but plans for its inclusion of earlier Galaxy S devices were scrapped because the implementation wasn’t good enough. Now Samsung can no longer be first, but, in my experience at least, it is definitely the best when it comes to in-display fingerprint readers.