Which Michael Phelps book is better: No Limits or Beneath the Surface?

I have to read an autobiography/biiography for my english cl. I know that No Limits is Phelps' most recent book, but on all of the websites Beneath the Surface had a bit better ratings. I'm a big fan so I actually want to enjoy this read, not just get it over with for my cl, so which do you think is best? thanks!