Only if you're raging. Most buff spells are likely to be cast in the first round or two of combat (or even prior), which means that you just need to wait till round two to start raging. After that, no worries.
And, as you've noticed, the big benefit of Superstition isn't the save bonuses (though those are really handy for preventing charmed barb syndrome), it's the rage powers you get access to. Lots of good stuff there, especially Spell Sunder (Wall of Force? Fly spell on the enemy mage? Prismatic Sphere? HIT IT SO HARD IT GOES AWAY).