From a classroom use standpoint the iPad and iOS major drawback continues to be the lack of Multi-User. You can't have students "log in" to any device. There has also been no good remote monitoring solution. In the "Mac" space just being able to have all the kids screens up on the a main projector (even at super tiny resolution) is an amazing deterrent to students trying to sneak off to social networking sites like Facebook, Twitter, or SnapChat.
Even as an ex-Apple-user I'll be interested to see how Classroom 2.2 has improved monitoring and control capabilities.
Google almost has the right of it with Chromebooks, but they're also missing a middle step that Apple is in a far better position to do (if they get back into Apple Servers). Mobile Tablets work best when they can be the lightweight front ends to a bigger beefier computer/data-system. They have just enough brains to be more reliable than a dumb terminal, but not enough to be truly flexible work environments (unless go out of your way to make them do so). Google's solution is to "Cloud" based, and outside the School or Classroom's local network. Apple should have been in a position with the iPad 2 years ago to tie them into an Apple (MacMini) Server that handles the majority of the student data. With only "just in time" local copies on the iPads themselves.
Never understood why Apple didn't sell iPads + MacMinis as college student solutions. In the dorm room the iPad becomes the "screen/head" of the MacMini. Walking about the iPad has just enough smarts for taking notes and basic word processing tasks. Most people don't need a full MacBook or Macbook Pro's worth of processing power on the go, but when they sit down at "home".
It is not quite as robust as using a Chromebook (where a user can sign in to any device), but Apple School Manager/Classroom allow a teacher to assign students to iPads and they can log in to the devices themselves. A typical example is a classroom that has a cart of iPads. A teacher will assign a student in each class period to a specific iPad in the cart. When a new period starts, the student just grabs their assigned iPad, selects their personal account, and types their personal PIN code to log in.
There are secondary benefits to ASM. Each student has their own Managed AppleID, owned by the school, not the student. It is a very limited account, for example, they have iCloud space, but can not buy anything from the App Store.
Also, using a Classroom assigned iPad, the teacher can remotely monitor the student activity, force a specific App or Webpage to open, or even remotely lock all iPads.
Here is a good overview:
https://www.apple.com/education/it/