As a longtime flashaholic I have to say my flashlights see less and less use while my headlamp collection seems to grow with headlamps of all kinds.
I don't think that the Petzl Reactive Lighting technology has any substantive problems with your breath in cold weather. It is true that it happens. It's not a dealbreaker. I have both the NAO and the Tikka RXP. If you are moving, your breath tends to dissipate before it hits the sensor. If you are stationary or working on something up close, it is already going to be in a fairly dim mode.
Under some circumstances like setting up camp, or similar arm's length stationary situations, it does become a bother, but a simple flick or tap puts the headlamp into passive mode. And that's not worse than using a normal headlamp.
You might find it weird at first that your headlamp tries to be smart about lighting. But once you get used to it, you'll find every other headlamp to be a bit frustrating.
My only real problem with the Petzl Tikka RXP is an ergonomic one. It can be difficult to find the buttons while wearing gloves, although the problem is mitigated by not having to fiddle with your headlamp often.