jar,
I like the Ultra-Dot fine, it has an 4 min. dot, which means it covers 4" at 100yds. I took many deer with it on my .44 and two last year with it on my 500. I have an Laser-Aim red dot with a 3 min. dot on another .44, but I just decided to use this one on my 500, it's worked out fine.
BTW, I set a 4 gal. pail out at 130yds. (measured with a laser range finder) and drilled it dead center, with my load and the Ultra-Dot on the 500.