Who uses a tablet PC?

Who uses a tablet PC?  My oldest is starting to make a little noise about having one but I don't know a Eee Pad Asus from a hole in my head.  Desktops and laptops?  Yup, I can find my way around those.  I am usually up on technology but I guess with money so tight the last couple years, haven't wanted to torture myself by looking around.  Is a tablet PC just like a computer?  Does it require any extra expense to run every month?  What are the pros and cons?

I figure she'll have to babysit for quite awhile to save up for one if she's expecting to have one.