Too late, already returned the ipad 4! It's true the size weight and portability is the deciding factor, even despite the fact that I got an ipad for home use. I find myself using the ipad mini more than the ipad 4, not to mention I've been using the ipad mini for a week and I just got the ipad 4 yesterday. This says a lot since the ipad mini novelty should have died down by now. I have a MBA 13 so the ipad mini probably complements it better.
The ipad 4's display is just soooo gorgeous, every time I pick it up I just fall in the love with the screen. Its easy on the eyes and text/pictures seem to just pop out. Movies and games look a lot better, was playing fifa 3 and the graphics is beautiful. But the ipad 4 is too heavy, my wrist got tired after holding it for a while, unless you leave it on the table, which I find my laptop would be of better use this way.