I have a smart phone and a wireless only Android tablet, which I must admit I mostly use for leisure rather than anything very productive, though I do use them for being available on email when I'm away from home.

I find the main advantage of the tablet is the speed with which I can get an internet connection and that it runs cool - no waiting for a computer to boot to do a quick google search, and I can leave it on a chair or the bed and not worry about it over-heating.

I also find the built-in GPS on my phone useful - for both car and foot journeys in unfamiliar places.