We have a Yoto and it's okay, but my complaint is how difficult it is to get custom stuff on there. The "record-your-own" cards are expensive (and often unavailable, like during this past Christmas season), and off-the-shelf NFC cards don't work perfectly (you have to ensure the content is downloaded onto the device before a generic card will work for that title).
it does take a surprisingly long time for the device to download the content for offline use, but my only real complaint is that I can't self host the server side (it seems to do some ssl certificate pinning or something similar).
