I have a 22/45 5.5" bull with a B-square mount and a "Target Sports" 30 MM red dot. I went to a gun show before I bought it, and I looked at BSAa, Redfields, tascos, bushnells, and the leoupold "gilmore" model.
After seeing them side by side, the only one I could tell a difference with was the Leoupold, but for the price, I would hope It would be better.
I have shot my 22/45 in the rain, cold, and heat, and its sight has never fogged up on me.
I couldn't justify spending more money when I couldn't tell a difference between the brands.