I honestly think they provide short cuts to learning and give teachers a distraction--let's see what we can do on the ipad rather than this is the lesson I need to teach, let's see how to best do that.
So, for that reason, I'm personally not liking the ipad, but that's just my bias.
However, there are safety concerns too. And yes, my innocent little dd and her friends are able to bypass security on it. Not to download apps or go where they shouldn't go, but to change grades and comments that the teachers give on google docs. I doubt the changes are in the "system", but the little perfectionists can make the comments read what they want them to read, and give themselves an A. I HOPE the teacher is able to see this if they care to look.
My second concern is about the messaging that goes on. The kids in a certain proximity can pop messages onto other kid's ipads. Like "you're a dork". My son figured out how to block it, so it can be done, but isn't generally. When we brought this up at a parent meeting, the teachers said that parents are responsible for the behavior of their kids. IOW, the teachers will not be monitoring this activity.
And of course the compulsive gaming--these are games that came with the ipad, not games that were downloaded. The ipads are synced regularly and apps are removed at that time. It needs to be written into IEPs and 504s that their ipads will be specially outfitted with filters and monitors or SOMETHING.
It was always my understanding that during school hours the children's behavoir was the teachers responsibility.