Summertime: Which is superior?

[GameMaster]

Question: What criteria did you use to narrow a song that's estimated to have been covered 2,600 times down to 15 artists?

In any event, I'll be honest, I don't have it in me to spend the 53 minutes and 29 seconds it would require to listen to all of these before making an informed and fair choice.

So I pick Eva Cassidy because I like other songs she sings.

Narrow the poll to 4 choices however, and I just might choose differently...

[DeathsHand]

Originally Posted by GameMaster

Question: What criteria did you use to narrow a song that's estimated to have been covered 2,600 times down to 15 artists?

They were the first 15 I located on youtube, and unfortunately the forum does not allow anymore than 15 choices per poll.
I'm considering posting the others (in groups of 15, of course) as I find them so that they all have a shot to be judged fairly as either superior or inferior to their peers.