Kindle 4 and kindle touch are equivalent the only difference is that kindle 4 have a button that you press to be able to shift to other webpages while kindle contact just as the name indicates you will have to contact on the screen to shift to other webpages. To determine on which kindle to buy you have to remember why you need it so that you can buy the best that will take care of your needs. Kindle will help you download, store, and study guides (e-books). With kindle you can easily study publications and sign up to publications. You can also study weblogs, play sound tracks as well as audiobooks.