Information on the ipad which is the best to use with fresco

Hi,

I am an applemac pro user and most of my work is in illustrator drawing and creating designs I want to start to use frescos as the artwork and brushes are the best for water painting etc but... Not sure what is the 1.  best Ipad to get ??

2.   Also fresco mentions psd file download also can it be downloaded to A1 illustrator files as well must sound like a silly question but havent read up on it yet

Any information  on the two questions would be great