Depends on the light. For me it’s a rare light that has a decent clip, so those are the only ones I’d tolerate with a sideswitch. Bouncing around in a pocket, then, means a tailswitch or twisty. Axial symmetry makes it easy to find the switch.
Side switches. followed (with small torches) by twisty’s.
Tail are a loong way down the list.
IN pocket. Twisty’s. on Belt/in pouch, Side.
Best option for me is tail switch for ON/OFF and side switch for mode changing,
ideal option would be tail switch + 2 side switches for mode up/down (I don’t like mode circling)
Just 2 side switches work for me also, like Nitecore EC21.
This works for me! 
Tail switch all day everyday.
So far the best UI that I have found is the HDS rotary’s combination of rear switch and rotary dial.
I don’t mind the side switch on my Zebralights and Emisars but I definitely prefer tail mounted when possible. That’s for smaller lights though; I don’t think a tail switch would work well on something like a GT.
I like e-switches with good UIs. I care more about that than where they’re located, but it’s rare for that to be on the tail. Of course, now I have an FW3A.
Depends on the size of the light .Small lights I've always thought side switches felt odd .Larger heavier lights almost have to have a side switch because of the balance and tail clicking a bigger heavier light becomes a strange two handed manipulation.
so the answer is ....Both .
I think that my FW3A is my first e-switch.
It's amazingly good!
Side switch is good but it should not accidentally turn on.
I like tail.
When people ask me, "heads or tails", I reply "I'll take a little of both!"
Hey, who doesn’t?
I use my EDC as a tactical light as well when necessary. Tail switch is essential. Also doesn’t get pushed by accident which is nice. I like dude stitches that change brightness.
Most of my lights have tail switches. The reverse clicky is fine. Sometimes it is not too comfortable to reach the switch.
I have an L6 … not exactly EDC, but I like its side button. It is a shame, that the on/off button is in its tail.
Some of my AAA lights have twisty head “switch”. Not as bad as I thought before I got the first one, but more-or-less convenient. If there were a switch around the place where you grab the head to twist, it would be very convenient.
Fact1:
Side switches tend to be e-switches
Fact2:
Tail switches tend to be clicky switches
Fact3:
Clicky switches tend to have long travel
Fact4:
e-switches tend to have short travel
I think none of these rules is universal. F.e. long travel e-switches exist.
I have a feeling that some anwers refer to the direct effects of location while others to what does location typically means (but doesn’t have to).
For my primary EDC I tend to prefer physical UI that doesn’t force me to seek the switch. So tail switch or twisty or otherwise easy to find (Tini side switch was great in this regard).
For the secondary EDC lights I prefer whatever is most compact. So usually side switch.
Side - only because it makes the light smaller.
I don’t have problems with pocket-activate.
I’ve had several side switch lights.
Tail - not preferred but then again my 2nd favorite UI (behind Anduril) is the BLF A6, which is a tail switch.
The advantage to tail switch is, you know where it is.
(though it’s not a big problem with side switch either - you can have the clip ‘point to the button’ so you can find it).
I have one light with both and I hate it - a Thorfire ramping light.
On off is via the tail, modes are done with the side switch.
I was kind of annoyed with the FW3A for having a tail switch.
It works well, but it has that inner conduction tube (seems trouble prone), which you would think could power a lighted button, too, but it doesn’t.
I would rather have a side switch and a shorter light, but that’s just me.
wle
I want both. That’s why I went for an M2R. Which I now don’t carry anymore because it’s too big for me. I only use tail switch for full brightness. Not switching levels no BS memory function. Full brightness.
Really wish Olight would start selling the M1R they have already shown, because I simply don’t need an 18650 or bigger as a pocket light. If I have to choose I would go for tail switch - which is why I bought the FW3A - I will put that in momentary mode and carry it like that.
I prefer a side switch, but I tend to carry my Zebralight more than my Emisar because it’s never accidentally turned on in my pocket.
Tail switches are fine too, but it often means a longer light which means it rides in my bag or jacket pocket.
I don’t care for twisty lights (I’ve only got one AA model and it’s not particularly easy to use one handed.)
I really don’t like a dual switch light. One on the tail and one on the side makes me have to adjust my grip and I don’t see the benefit of it. It’s keeping me from buying a Sofirn C8F.