Don’t have the S70 or L6, but have a few Q8s.
The Sofirn is cooler/bluer but throwier, whereas the BLF/Thorfire is warmer (neutraler?) and floodier. I prefer the latter on both points.
Was tempted to get an L6, but I rarely use my L2s or even the Q8s unless I NEED a mega-light. Most times I’ll just grab for my Cometa as a “big” light.
So, it depends on what you wanna do or use it for, other’n being a “Wow!” light to show off to people.
The Q8 fits, albeit very snugly, into a grenade pouch, so you can MOLLE it to something else hang it off a belt. Don’t think you can do that with an L6 or other bat-light. Also fits nicely into a jacket pocket.
Bat-lights need matched cells because they’re running them in series, but the Q8 has all 4 cells in parallel, so they’re naturally going to be and stay matched inside the Q8, from fresh-out-of-the-charger to having LVP kick in.
I never even played with the Q8’s UI. Click on, 2click for turbo, press’n’hold for ramp up/down, click off. Never even looked at the manual that came-with. Other options? Yeah, probably, but I never bothered to mess with ’em.
So, you wanna whomp something/someone on the head, get a bat-light. Else the Q8 is nigh perfect for hella-bright yet still jacket-pocketable.