Pacsafe is by far the best quality out there for security travel bags.  I own 2, the very small metrosafe 100 which got me through Italy feeling like I didn't have to keep my hand on my bag all day.  I also own the Metrosafe 250.  It is overkill for carrying an ipad, too much room and kinda heavy.  The slingsafe would have been perfect but the ipad won't fit.  Someone needs to really evaluate travel needs for tablets and ipads, the selection out there is poor, so I bought the Travelon React Small Messenger Bag.  The security clasp broke the first day.  But the size was right!