If you just want to hand-held it without any support, then the iPad + Case combo is indeed a bit heavy, but not to a point that you cannot tolerate. However, in reality, I usually would have some supports, either my laps, or the table. I don't think anyone would walk and use an iPad like they use an iPhone too often.
The only complaint I have regarding the Apple iPad Case is that you cannot "lock" it. It would be perfect if they can add a velcro or a button that can secure the cover.
Nikon D700 | 105 f/2.8G VR | 24-70 f/2.8G | 70-200 f/2.8G VR II | 50mm f/1.8D |