Probably because they are rather new on the scene. Frankly I'm waiting to read a few more positives about them before making a purchase. I need to replace my Fenix L2D which has left me a bit gun shy on the Fenix line. Currently want to add another 2xAA light to back up my Nitecore, which I bought after the first failure of the L2D. I also am looking to add another 1xAA and another 1xCR123.
Well I havent read a bad thing about them yet. After playing with the 1xAA a little more I have some pros and cons.
Pros:
-Small Form Factor
-Sturdy Pocket Clip
-Good output and runtimes
-Feels solid and not cheap
-Tactical UI is great (cant chime in about the normal one)
-Comes with spare o-rings, finger-grip, holster, lanyard and 1xAA.
Cons:
-Tough forward-clickie button
So I have not experienced too many issues with the light. I just wish the clickie wasnt so tough. Its pretty solid and im sure the people at candlepowerforums and flashlight-forums have some more info.