I've got a 3M full-face respirator as well, and I agree. I've worn it with P100 filters for 8+ hours (minus breaks to drink water) doing hard work in uncomfortable conditions many times, and never found the respirator to be a burden.
They're a little pricey up front, but I figured it was cheap overall compared to the long-term costs of using something less effective. Having eye protection integrated as well is ideal, since it never fogs up.
I got one of their FF400 face shield respirators to do lead paint removal and spent dozens of hours in unconditioned spaces with a tyvek suit. They are extremely well designed and never fog because the inhaled air passes first through the face mask area and then through one-way valves into the mouth/nose section and is exhausted downward at the front of the mouth/nose area.
I used it during the beginning of COVID to protect myself up until I was vaccinated and went for about 18 months before getting infected. Definitely got some odd looks at Costco.
Maybe you are meaning for medical staff? Yeah there's a fully unfiltered exhaust stream blowing downwards.
They're a little pricey up front, but I figured it was cheap overall compared to the long-term costs of using something less effective. Having eye protection integrated as well is ideal, since it never fogs up.