I didn't mean to own a ton of Petzl head torches, but I accidentally have ended up with a drawer full of them. From the diminutive Tikkina, the nice-but-dim E-lite, the fantastic Zipka, the battery-hungry Myo and now the smart Nao. The Tikkina is your bog-standard head torch, the E-lite is the tiny one driven by a watch battery. The Zipka is the brilliant one with the little elasticated cord that winds up internally instead of the usual stretchy band, and the Myo was the very powerful one, until the Nao got released. I also have a pair of no-brand CREE XM-L headlamps with a claimed power of 3800 lumens (compared to the Nao's 355 lumens), which are great for frying eggs on or tattooing the pattern of a heat-sink onto your forehead.
The Nao has some idiosyncrasies to absorb, and I think for some people these little niggles will turn out to be massive show-stoppers, and for others they won't even be noticed. The absolute major niggle is the actual responsiveness of the light. This is the touted 'reactive lighting', and in case you haven't heard of it, it means that there is a little sensor on the headlamp that detects how much light is coming back in your direction from the environment ahead of you. The idea is you look down at a map, the amount of light reflected is high because the map is close, and the Nao detects this and turns the emitted light down. You look up to see a distant object, the Nao detects a lack of reflected light and maximises the emitted light.
This works really well, but it feels really weird at times, especially when you first use it. When you are actually doing something, like skiing around at night, or skating over a lake, and you are looking at your watch and at your feet and then at the landscape, the Nao responds amazingly well. It's so fluid that it feels pretty natural after a while. Sometimes it can fuck up, like when you breath a condensation-laden breath out of your lungs and the light reflects off that and dims itself needlessly, but this kind of thing turns out to happen less often than you would think, and again, it's just something that will either annoy you, or not annoy you, depending on the state of your anus.
Sometimes it works less well, if you're just reading a map solidly for five minutes, or a book for that matter. Then the jittery powering up and down of the light feels like something has broken. In fact it feels exactly like there is a loose connection in the torch, or a battery is not perfectly fitting in the battery compartment. That kind of thing can drive some people bananas. If you're the kind of person that gets upset at messy desks, late trains or toothpaste tubes being squeezed in the middle, then the Nao might not be for you. Until they rub some bugs out.
Personally, once I got used to the flickering and trained my brain to lose the connection between a flickering light and a dodgy wire, I loved the Nao deeply. Flickering was not really noticeable after a few weeks. However, even a year into my Nao experience, I still get a visceral pleasure in seeing the torch respond to where I look. Looking down at a map lit by a gentle glow, looking up and without the slightest lag, seeing the view in front of me lit up like a prison yard after the escape alarm goes off. This is good, useful technology.
I have to also compared it to the crazy power of the 3800 lumen headlamps, because you might think more light is more better, but in my opinion it ain't. The Nao is hardly dim, and the usefulness of the reactive lighting makes it indispensable once you grow to rely on it. Whereas the 3800 lumen torches just feel like really powerful old-school torches, great for something like mountain-biking (which is what they are designed for), but not so useful for the more intricate activities the Nao is designed for (wandering around a misty moor referring to a map every few metres while pretending to not be lost). And no way in fuck are they ten times brighter, I imagine Petzl are a little conservative and Noname brands are maybe a little eager to exaggerate. Still, 3800 lumens packs a punch. They basically feel like high-beams on a car.
The power of the Nao comes at a price though, the massive 3.7 V, 2300 mAh battery gets eaten up in no time. The reactiveness can stretch it out, and of course you can set the torch to run at a lower power setting to conserve energy too. If the battery does get finished though, you can fit AAA batteries into the pack to run it on a low power mode until you find a handy USB port somewhere in the forest. Or you can buy really expensive spare Nao batteries, or hack it to accept other batteries. Those 3800 lumen torches take four of the Nao cells by the way, and last a bit less on those four cells.
The actual design of the torch itself is rock solid. The connector for the battery pack feels like something that should be connecting military hardware, and the on/off/state button is big and fat and easy to use with gloves on. The cord-system they have for clamping the torch to your head is much more comfortable than the elastic straps on the other Petzl torches (and feels like a head massage compared to the razor wire in the Zipka). And the front of the lamp articulates up and down in the same way the Myo did, which I find very handy. It doesn't work for helmets sadly, which kind of sucks because that would be a very cool use for the torch, the insane power would really lend itself to climbing when you want the wall lit up like a christmas tree. The Nao has a 'splash' resistance, which usually means no kind of water protection at all, but as usual Petzl seem to have a pretty high standard because there are plenty of little rubber seals on the Nao (and check this video out).
One last thing, the Nao gets hot. It won't burn your forehead, but I can imagine that the torch would have serious problems if it was on maximum power and stuffed in a pocket or a rucksack. As the strap is super comfortable you can put it on under your wooly hat and enjoy a head-warmer bonus feature.
The bottom line with the Nao is, despite the flaws it's so good you won't be able to come back from it. After a few months of wearing it, of getting totally used to having the light jump up when you look around the campsite, and throttle back when you go back to whittling some wood, you won't be able to go back to normal torches. It feels like going back to a Nokia 3210, or back to a minidisc player, or not having Spotify. You mean I can't play GTA on this fucking phone? You mean I have to manually change a fucking disc if I want to switch albums? You mean I can't access every song ever whenever I want? A few months of the Nao and it will be 'You mean I have to fucking press buttons on my torch to make it do what I want?'. I love the Zipka and Core combo, that I actually use quite a lot still, but only for reading a book or something like that, where I want little power for a long time. As far as a torch for hiking, kayaking, skiing or skating or whatever activity you want, the Nao has basically made itself the only option for me.
There used to be a dozen good contenders for use in those kind of situations, but now there is only one.