VP8 vs. H.264

A head-to-head comparison of the VP8 and the H.264 codec concluding,
"H.264 still offers better quality, but the difference wouldn't be noticeable in most applications."

So, if it's the difference between free and open source, and for-pay with very little noticeable difference, VP8 wins.

But if it means less battery-life and increased heat because the decoding has to be done in software, then H.264 on the iPad wins.