As fond of iPad bashing as I am due to their lack of openness, some of the comments point out how software (even open source software) present themselves as homogeneous blobs, written in inscrutable C++/Java/whatever incantations.
It can be argued that such is the state of the art - we've moved on from punched cards, at least.
But neither hardware nor software particularly lends itself to education, it's all about getting it done, protecting your interests (complexity brings obfuscation, a form of encryption) and waiting for fashion to move along so you can do it again in another language/paradigm/form-factor.
To really make a difference in education, fashion would need to make an unexpected turn - favoring the users, which won't happen as long as they're consumers, in whatever form.
Two things would make this happen
1. Tin of beans guarantee - it contains what it says on the tin
So an iPad would have "consumer appliance" on it, which is what it is, not for IT education
A Raspberry Pi would have "IT kit" on it
2. Be amenable to tweaking/tinkering/reprogramming/developing-software-on
Ordinary PCs go some of the way, the Raspberry Pi goes further, and with OpenCL it would go all the way.
Ultimately only open software on open hardware can seriously claim to earn the badge "an IT educators must-have".