If someone is using a tablet as their only computer, there are a few features that may not ordinarily matter that much, that you should think about.
For one thing, USB storage: lots of people use USB drives to move files around, so you need to be able to read them. A standard USB port is a must. I think that rules out the Apple's products (there are workarounds, but, that is probably not what someone wants from a first computer).
You may want one that either has mobile connectivity built in, or that has drivers for a USB mobile dongle - depends on usage pattern (hard to predict) and how common wifi is where they live.