Kay, just my thoughts. Not only is Expo 1st, but 
it is like the biggest Anime convention in the US. 
Everyone will bring their best stuff, and I 
guarantee it will get snagged before Comicon. 
Besides the fact that Comicon is really more about 
comics than anime, I would naturally expect better 
cels at Expo. But that's just my opinion, I could 
be wrong...