Let your intended use depict the power of the scope, Brushy, close range use low 1-2 power or no scope, longer range go stronger (with sticks)
I use a Burris 2x on my SBH, cheaper scope--no problems.

If a quality variable is in your price range go with it. I have two Nikon's in 1.5-5X and they work real well. If you're going with a fixed, I'd also suggest a 2X for reasons already mentioned. I've owned two 4X scopes and they were fine at the range, but were very hard to hold steady off-handed. As for brands, I've owned Nikons, Leupies and Burris' and they've all been good to me. I've also heard good things about the Bushnell Elite, but have no experience with them.