If I had a lot of painting/priming to do, personally I would use nothing but a hood or mask with a fresh air system. Period. Filtered respirators are too flaky. You have to worry about changing the filter. You have to worry about making a good seal. Have a day's worth of stubble? Your mask is useless. It must hold negative pressure if you suck in and block the vents. I'll bet very few mask users actually pass that test.
I'm only doing very occasional priming so I use a filtered mask. Just a standard painting mask from Home Depot/Lowes. It has a particulate pre filter followed by an organic vapor filter. Very standard for this sort of thing. It must be stored in an air tight container. The filter must be changed very often.
If I ever go back to a slow build kit and have a lot of painting to do, my first purchase will be a fresh air system, used or otherwise.
Work safe and stay healthy.