I have tried different tablet devices in the past and I see very little benefit from them for the majority of people. The iPhone/iPod touch seem to be just about as big as you need for a productive web surfing and media consumption device and a tablet Apple really does not make much sense to me.
I do think the handwriting recognition found in Windows Tablet PCs is actually extremely accurate and quite remarkable. That said, I am still way more accurate and productive on a QWERTY keyboard and find little benefit in handwriting on a computer screen. The convertible Tablet PC devices do give you a full notebook experience along with a tablet experience, but these have never seemed to sell that well and are priced quite high compared to a comparable netbook.
Does anyone think a tablet device doesn't suck?