AAC (MPEG-2 Part 7 / MPEG-4 Part 3 AAC) is superior to MP3 (MPEG-1 Audio Layer III), giving better sound quality, especially at lower bit rates and higher frequencies. MP3 is a very old codec started in the 80s. Time to move on. True, there are other modern formats as good, but they aren't as common or widely supported.
I didn’t say the MP3 was the best, I said it was the standard. After all, the iPod is commonly known as an MP3 player, is it not?
As far as what is best, that is subjective, you are welcome to your opinion.
If I am going to listen to music with earbuds, I can’t hear a difference beween MP3 and AAC. Now on the otherhand, if I go down to the music room and fire up the receiver, I don’t bother with AAC or MP3, I listen to CDs or BDs.
We’ve drifted a long ways from a TV out on the iPad. I’m still for it.