To each his own. I'm 71, but I've been playing with computers since before the Internet for the public. Fortran, Basic, TRS-80, then PCs. I have absolutely no clue about Macs, other than they're expensive "computers for dummies".
I've never tried using an iPad, but don't find a friend's Playbook intuitive at all, if that's similar to how an iPad works. The Vox, however, I find very logical. However, it really depends on what a senior needs. If it's just to read books, then a Kobo Touch would seem to be a better product, without all the unwanted baggage on the Vox.