Sudden Empower (or Empower in general) is the superior feat for spells with a 1dx+y mechanic, such as ray of enfeeblement [1d6+(0.5*caster level)], false life [1d10+caster level], fires of purity [1d6+caster level], or the previously mentioned spell turning. This is because of the quirk in the rules that empowers the "y" component of those spells, while maximize has no effect on them. It's only really corner cases, but they do exist.