The TLR-8 has two switch styles, they call them high and low.

Does anyone have an opinion of what one works better?

I am planning of putting it on a P320C if that makes a difference.

I use the TLR-7 (same thing as the TLR-8, but without the laser) and I prefer the high switches.

You will find discussion of the subject here. I use a TLR-7A on a Glock G19. Initially, I though I would like the high switches better, but in actuality, the low switches turned out to be preferable. You will see in that thread that at one point, I had a high switch on the right side and a low switch on the left side (I am right-handed), the reason being that when I put my finger thrugh the trigger guard, the nail of my finger snagged on the high switch on the left side of the trigger guard. Ultimately, I opted to have low switches on both sides, as I discovered that the high switch protruded too far back for me when I opted to activate the light with my trigger finger.

So, for me, on a Glock, the low switches are preferable. Now, it does matter what type of pistol you are mounting the light on. For example, here's a TLR-7A on a Walther Q4 SF.. You can see that the high switches appear optimal, as the low switches might be too far forward for comfortable activation of the light. I couldn't tell you about this light on a P320. While you can purchase the TLR-7A and TLR-8 with either low or high switches alone, you can also purchase the "FLEX" model, of these lights, which have both the low and the high switch bodies and you can change them at will.

I tried both on my P320C with X-Compact grip, and strongly preferred the High.

But it will vary from person to person. Get the Flex model, try them out on your gun, and decide for yourself.