i have ipad, samsung galaxy 10.1 and smasung galaxy 7.7.

so from experience i would strongly recommend 7.7 it is GSM and capable to do almost everything, above that the graphics is super amelod which is similar to the ipad.

the add value which i consider it a huge advantage is that you can buy with 47 qar 4in1 adapter for the 7.7 so you can connect USB to your device (copy/past) or wireless mouse with keyboard
it is amazing just go with 7.7

hope i clarified things for you.