I have a Streamlight TLR-7 mounted on my P-07. I ordered it from Amazon in March, and it did have the flicker problem when it was new from the box, whenever dry firing or racking the slide. I contacted Streamlight, and they sent me a new cap with a much firmer spring, within one week. Since then, I have put around 800 various rounds through two different P-07's with it attached, and no issues.
The switches could be better, but I find that I can easily toggle it with my support hand thumb, or ride it with that thumb as I am live firing.
My other issue was finding a decent kydex IWB holster for the pistol and light combination. I ordered one off of Amazon from Neptune Concealment, their "Triton" series. The overall quality is decent, but I did have to remove about a quarter inch of kydex from my strong (left) hand side near the trigger guard to get a decent firing grip. I also put Vibra-Tite VC-3 on the screws and some foam rubber tape over the backs of the chicago screws, which is something I have also done to my other IWB kydex holsters.