For predator hunting, I like a 2.5 to 10 power, or a 3 to 9 power scope. My experience has been that predators will generally be encountered at shorter ranges (under 200 yards), and the lower power on the scope is used the most.
As far as brands, I have Bushnell Elite scopes on almost all of my guns. I think they are very good quality for the price. Just recently purchased my first Vortex Viper PST, and am very impressed with it so far.