I have both an iPad Pro and a Microsoft Surface Pro 3 tablet running Linux. Depending on what I am planning on doing on a day-to-day basis affects which device I carry around. Mostly I carry my Surface, as I have Linux installed, and it allows me to easily do development, remotely administer machines, or do general computing tasks. The keyboard on it isn't great however - it's kind of flimsy and doesn't work well if it's not on a firm surface. I can't easily use it on a train for example. It was perfect when we were in Australia for a month, and allowed me to both work and do University assignments. I can use it as a tablet for reading, but it isn't great for that.
The iPad Pro on the other hand, is the perfect media consumption device. I use it to read books, watch videos, study, and play games. I've found that it is absolutely fantastic for study. I tend to download lots of PDFs to it, and then annotate the PDFs with the Apple Pencil. I can use the VoiceDream app to read out the PDF I am studying to me, which forces me to read it in more depth than I would otherwise. The battery life of the iPad Pro is far superior to the Surface. At least one running Linux.
It would be great to have just one portable device that fulfills both functions, but currently I find that the combination of both of these things works well for me.