The worst muzzle flip that I've experienced was on a .300 Weatherby, as it was a light rifle, had a stock with a big comb as I recall so the drop was more than on a rifle, and had a lightweight tapered barrel. Definately designed for looks and carry as opposed to shooting. I was shooting it as the guys who brought it to the range were flinching so bad that they couldn't get it sighted in.
My 30.06 target rifle has a heavy barrel, a straight stock, and is comfortable to shoot when going thru over 80 rds at a shoot, including rapid fire. Definately designed for shooting and not for looks or carry.