Want to read an ebook, check.
Want to watch your favorite show or movie, check.
Want to do your office work, check.
Want to email or browse the web, check.
While the Vita can do some of those things like browse the web or watch shows and movies. Its much easier to do on a tablet with the keyboard along with having a much bigger screen. The other things the tablet can do that the Vita can't justifies the difference in price.