Here is the feedback which I got from all three of them:
Nas:
. Nice design
. Used the keynote for what it is.
Amar:
. Good idea for people to submit their own designs.
. Stock them? Market towards being fun.
. Too similar to talking tee's. Make it different.
Sam:
. Lack of confidence which made presentation weak.
. Target audience should be 14-20, not as broad as you said.
. Target holiday groups and analyse 19-20 year olds going to ibiza.