got me a Fuel non-high-speed. Its massive and heavy but I trust it using it manually. Using it manually is the most important to me, because I feel any time saved with others then swapping to a hand ratchet to break/tighten are negated.
I’d probably choose high speed if I had the choice, because its nicer to zing up and then tighten by hand than run the impact up hard, jerk your knuckles into something, and then check tightness by hand anyway
Speaking of which & not that it actually matters cause we all do it with any powered ratchets anyways. But with the 1st gen Fuel, MW never stated it was ok to use it manually. When asked about it they only said they don't recommend it. Basically that's their answer just to cover their *** when need be.
With the High Speed Fuel, the specs actually do say it can be used manually. If you compare the 2 you can see MW made changes to the body/case & with bigger screws. Or maybe it has nothing to do with it.

When I had the 1st gen Fuel, I still used it to break free & tighten fastners. Although it had more torque it still wouldn't break fasteners loose for me many times. And I never trusted it tightening, I always snugged up by hand so the "higher torque" was useless to me.
I used air ratchets, & now cordless to speed up turning fasteners, so I rather have the speed, again tightening & loosening done manually. Some say the high speed may be too fast for their needs but keep in mind the trigger is variable speed, you don't have to go full send if you don't want to.
At work, my high speed ratchet is my second most used tool, some days it's the most used. I use it on fastener sizes from 5.5mm to 19mm. I deal with nylocs often & never had a problem running them on. Most of what I deal with is smaller than 14mm head size which will mostly break free with the power of the ratchet. Many of the fasteners I can tighten with the power of the high speed ratchet & be fine, if it had higher torque no.
No way I would go back to using the 1st gen Fuel for what I do (I grew to hate it anyway). But again, no rust here, & the vehicles I work on are new. If my HS broke tomorrow, I'd buy another one right after work.
And the fact that there is a tall shift knob for it is another huge plus (stupid MW should have included it). Today I had to use my coworker/team mate's high speed ratchet. I had forgot what it was like with the stock recessed shift knob. He didn't know about it & when I showed him mine he immediately wanted one.
It's not perfect but I still like it the most for what's currently available. Other coworkers have Makita, Snap-on, & Dewalt. One downside I have run into is when running SS nylocs onto SS screws 1" & longer, I have run into galled threads quite a number of times. Learned my lesson having to cut them off. So now I just remember to run them on slower with the variable trigger and/or add some oil to the threads.