i've had one for over a month now - i know, not a very long time.
thus far i've developed no switch problems. the following are merely some observations based upon my particular biases in what i like and/or don't like in a light.
1. in it's max o.p. mode it is very bright indeed. claimed burn-times reasonable - no complaints there if it lived up to the claims (by this statement i DON'T mean to imply that it does not live up to them, rather i'm merely stating that i haven't yet verified that it will burn as long as claimed by the Mfr.; i don't have any doubts, at this point, that it will burn as long as claimed).
2. it's minimum mode is low enough for most tasks.
3. it appears to be very well constructed - fit and finish is excellent in mine.
4. due to resistance provided by even a well lubricated o-ring, one handed operation on my particular unit is difficult, particularly when it comes to adjusting the light o.p. in its ramping mode.
5. UI is a bit anemic, IMO. those two new models others have already mentioned are a big improvement, IMO.
6. having to use two different switching mechanisms to operate the light is a bit of a minor inconvenience since it is not just that two switches (tailcap and rotating head) are req'd to put the light through its paces, but also that it might be desirable to change the position of the light in one's hands after switching it ON, and then again to switch it OFF - or use two hands for ON/OFF as well as for adjusting the light o.p. in ramping mode.
7. maybe i missed something, but i tried the NE head on a SF 2-level Cree E1L Outdoorsman. i could only get the MAX o.p. level to work. i lost the second adjustable/ramping level mode of operation. if someone else also pointed this out, i missed it. to me this is an issue since i don't always want 200lm of light. anyone, if i've missed the boat on this point, please Post back and educate me on how to get "ramping" o.p. adjustment mode with a SF E-series body.
bottom line (for me): not my favorite 1xCR123A due to UI limitations, but definitely the brightest. i certainly don't consider it money wasted. even knowing what i know now, i would still purchase one. however, its idiosyncrasies, in terms of UI, caused me to pull the plug on acquiring a NDI, but i still intend to purchase one (or both) of the new lights w/the new UI even though they are not 200lm lights.