Of the few different tools I've tried, I also prefer the Lee safety Prime, mounted on the Classic cast turret or the classic cast single stage. The handle is adjustable 360º, so I have found that if I adjust it, just so, where the handle ends up near the rear support post when the primer is being seated, you can grasp that post with your fingers, while your palm is still on the handle, you get incredible good "feel" during seating and all the machanical advantage of the linkage to eliminate any fatigue.
But, as far as the OP's question, I prefer the Lee hand primer with round tray for "off-press" priming...is it the BEST? IDK? I do know it's obsolete as far as Lee is concerned, and they no longer sell replacement parts that were specific to that design, so I will buy up any of those units, when I see them at the gunshows...I've probably accumulated a lifetime supply...especially since I do 99% of my primer installation on the Lee classic Turret.