If the user is going to use it not for phone.
Iphone is very good, it can put in the pocket. They can always be with me. Tablets need a bag. But display is too small even it is Iphone 5. It is too small to use it for websites, even photos, videos. Iphone 4 are cheap but, with price of Iphone 5 I can buy tablets. There are smart phones that has large display, but they have low battery life.
If the Tablets price are same or cheaper, it would be better to buy Tablets?
bad thing about tablets is it's large that people will see it easily, won't have a privacy.
Added (1). tablet
См. статью: Are Kindle Fire and toublet better than Iphone?