The P12GT has an annoying delay between the time when the switch is activated and when the LED fires. That makes it unacceptable, to me, for serious usage.
For me, the Fenix PD35 TAC is unacceptable as a defensive/tactical light. If I understand the UI right -- and please correct me if I"m wrong! -- when in "tactical mode" or whatever Fenix calls it, each press of the tailswitch changes modes. No one I've ever trained under would find that acceptable. Momentary-light-and-move is a pretty standard doctrine, and if the light modes progress while doing so ... like I said, I don't consider it even in the running for a tactical.
In tactical mode, to switch modes you need to quickly press the tail switch repeatedly to cycle through turbo, strobe, and low. But if not done quickly, every time you press the button (either half press or full press) it comes on in turbo mode. There still is a possibility a person could end up in another mode unintentionally though. I'm not a big fan of the tactical mode, but maybe it works for some people.
But you can also put the like in outdoor mode, in which case it would work no differently than the P12GT, where the side switch selects the mode which is remembered - then the tail switch can be used to switch the light on, off, or momentary.
Oh! Thanks for the correction. Ironic that "tactical mode" is the one I'm questioning for tactical use. But I just watched a video, am I right in thinking that if I keep the light in momentary mode (no full clicks), it will just always come on in high, no matter how quickly I use momentary to turn on and off the light? And only a full double click gets to strobe? That doesn't sound as bad as I thought it was. Maybe the only further concern is if I"ve double clicked into strobe, and want to go back to turbo, I have to double click past low then double click again, and that's lots of little clicks under a lot of potential stress. Ah well.
But anyway, if in outdoor mode, the tailswitch only controls on/off, and if in addition the thing has memory so I can pre-set the light so I"ll know it will turn on in turbo (exercise for the reader whether to accept the risk that you'll forget to do so), it can work...
No, sadly it will cycle through modes by either quick full presses or quick momentary presses of the switch. But if you release it (either from fully engaged or momentary) and wait a little over a second, it will always start again in turbo. It really is an odd UI that takes some experimentation to understand. The manual doesn't do a good job explaining either.