The worst of the worst are JR Sport servos.....they didn't even make it through a gallon of fuel before the bushings wore out on a sport plane of mine. Even though they were dirt cheap, what a waste. I've never seen servos wear out so fast.
Hiteks are generally a good bet. I think it is cheaper in the long run to buy ball bearing servos, especially if you're going to really throw that plane around. As stated above, make sure the linkage is stiff and tight. Set the throws up mechanically with the right ratios to give the poor servo as much mechanical advantage [leverage] as possible. More throw than the plane can use puts a strain on the gear train and hurts control resolution.