A real P&S ISO dilemma. Help.

Of these two cameras(and only these 2), which would likely give me better images in their respective higher ISOs? S2IS or A590IS? I realize that they are vastly different. But they would be called upon to "try" and capture the best images that they could, of grandkids stage performances. I know, I know. DSLRs are best for this. And I do have and use them when I can. But for that occasional situation where one of these 2 cameras would be better used, which one would deliver a better product at a higher ISO. I'm thinking ISO400 max. No flash.
Thanks