I've given it some moderate use, around the house and as a bike light. No signs of wear or difficulty at all with the switch so far. I am still annoyed by the ~0.5 seconds you need to hold the switch down to turn the light on or off. But it does the job and has prevented accidental lighting, even when bouncing around loose in my bag.
Mode switching and on/off have both been rock solid and predictable.
As a bike light (attached with twofish lock blocks) it's been surprisingly nice. I thought the spot would be a little too bright relative to spill, but the spill is quite bright on its own, and the spot is large enough to turn into a beautifully big oval extending well ahead on the road. In about 5 minutes I made a very high-tech shield out of rolled cardboard lined with aluminum foil that I can slip over the head. With the light pointed far enough forward to make good use of the spot, it's pretty much mandatory to block off the glare to oncoming traffic, and this setup works surprisingly well. As a bonus it reflects a good bit of light onto the front wheel and ground nearby, which makes the bike much more visible from all sides even if it's not much use to the headlight function.
