We bought 3 of these (one for a 7 year old who poves to write/draw), and they've been easy to set up and great so far. To utilize, you will need to link to an online data saving space (like Google Drive), so you may need to set something extra up if you intend to use it for a child.
The instructions mention that you need to let the ink dry fully to avoid smudging or transfer to the opposite page when you close the book, and that is true. We have had a lot of points of transfer, but if you want a minute or two, you can avoid that. It isn't a huge issue, but something to be aware of, especially if you are a lefty and your habd will slide over your previous writing as you take notes (likely will have smudging).
I do wonder about how to get replacement pens, and if other erasable inks would work (like wet erase markers?). Obviously, the one provided will eventually run out, and we'll have to cross that bridge when we come to it. ;)
Wish they'd have made a way to clip the pen on or fit it inside the spiral binding, but that's a first world problem.