I was wary when unboxing my iPhone 5S that what I would find inside would disappoint me a little. The phone is, after all, very similar to the iPhone 5, and I’d been running iOS 7 for months—so even its new, bold software was familiar. I was also excited, and tore my way through the wrapper and box and plugged it in as soon as I could. But there was still a little tickle of nervousness in the back of my mind.

Silly me.

The moment I first unlocked the phone with my fingerprint, the iPhone 5S made perfect sense to me. Quite apart from the ridiculous, seamless speed which which the thing reads and recognizes a print, it was the act itself that logically clicked into place. I’ve jabbed at the “home” button for years, exiting apps, waking the phone up from sleep and, recently, double-clicked it like mad to bring up different iOS control features. I’ve also typed in my iTunes password so many times that I could nearly manage the feat by muscle memory alone—zipping the 10 letter code into the machine in a second even on the touchscreen keyboard.

Now to unlock the phone took just a dab of the fingertip on the button I’d have pressed anyway. And to buy an app from the app store it was just another dab. And to buy music—ditto. My poor work-stressed typing fingers instantly enjoyed the experience.

But can you build a whole phone around a simple feature like this? No.

And that’s where the rest of the iPhone 5S’s new powers made sense. The very first time I saw the icons of the desktop “bounce/zoom” onto the screen I was aware that there is a very smart bunch of chips inside this device. I felt a quite definite tingle that I was holding something powerful—a sensation like the first time I ever opened the shutter on the particle accelerator experiments I once ran, flooding my samples with beams powerful enough to shatter the very air molecules apart.

But the iPhone fits in your pocket. It’s a wonder that miniature fireworks aren’t erupting out of its ends all the time.

There is simply so much speed. Apps open in an eye-blink. Games with graphics that look like those on my PS3 run smoothly and without a graphical twitch, their colors and minuscule details rendered deliciously. User interface structures flit onto the screen, get tapped and flit off like they’re in a rush to get somewhere. The camera app is open and ready to take a shot at the same moment that I notice the thing that prompted me to take a photo anyway.

And that’s the first time, with almost any camera I’ve owned from top-end DLSRs to pocket digital ones that this is true. With my iPhone 3G I managed to snap a photo of my son’s first steps ever—but only about the 8th one in, because it took so long to get the phone ready. With the 5S I could probably have caught the end of the very first step. In slow motion video.

Using the camera app is simply delightful. It’s not flawless, and I found the UI doing odd things like switching to video mode when I was actually trying to zoom the image. But it’s still the best camera I’ve ever used. It’s actually fun to snap away.

Playing games on the iPhone also, finally, makes sense. I’ve played many, for years, on the iPhone but I’ve often downloaded the bigger ones with a sense of unease that I was giving over a large amount of the limited storage space in the phone to an app I’d play for a bit, before stopping because I was either disatisfied with the slow game play or the graphics. That sensation has gone already.

The 4G speeds are faster too, or so it seems, and while my iPhone 5 struggled to get a Wi-fi signal from my home network while I cooked down at my outdoor oven in the garden, the 5S manages two bars of signal. So I could now watch our TV-over-IP app while cooking, and stream music without worrying about eating up my 4G allowance. A little Vivaldi was a great accompaniment as I got the fire up to heat (and snapped a slo-mo video of its flames rolling).

Compared to the older iPhones I’ve owned the iPhone 5S is just more perfectly polished than any of them. It’s faster. It somehow seems like a more tightly wrapped package—every bit exactly in place. I imagine the circuits inside it fizzing with electricity when I hold it. Did I get this sensation when I upgraded from, say the iPhone 3G to the 3GS? Yes, for sure, and also for the 4S to 5. But the leap this time is a much bigger one, and it’s slightly off to one side. The 5S is so very good as a device that it easily surpasses the improvement its predecessors demonstrated over their predecessors. And as app developers optimize their code for its better CPU then I guess that sensation of speed will persist over time.

Can you get as good camera performance, a great screen and a useful and user-friendly UI on rival phones? Absolutely, and in some cases you may feel a particular phone’s camera beats Apple’s or that its screen is bigger or brighter or more ideal for your uses. I’m not so sure you’ll get as consistently tight a UI experience elsewhere, though. Because though some geeks will gripe about it, iOS 7 feels so very satisfying to interact with that I feel the general public (the folks Apple makes things for, remember) will love it.

And that leap to the side I mentioned? It’s a little theory I have, a sensation about where the iPhone’s future lies.

After owning the 5S for a day I feel like Apple has got the iPhone to a peak in its current format. I once wrote that the smartphone revolution was, in a way, over—every touchscreen smartphone nowadays is essentially a copy of the format the iPhone came with back in 2007. And I suspect the 5S is kind of the end point for this. Apple could make the iPhone 6 a thinner, lighter, more powerful iPhone with a new body design and a better camera and so on. But I don’t think it’s going to. It’s time to try something bigger, bolder. That’s the only way it can keep the phone relevant after making the 5S, which is so very, very good.