I like the iPad for some things. It has a very good interface, very responsive. Very simple to use. The apps are wonderful, though navigating the iStore is an eyesore. I think it comes down to what your nephew has for his priorities. To be more in the crowd, he might want an iPad.
I don't like the iPad because it is a little hit and miss for reliability. Make sure you extend that warranty. It doesn't have the same history as their other hardware. Overall, people seem pleased enough, though. Mine died the first week I bought it. Fortunately, Verizon simply handed me a new one (after nearly an hour fiddling with the first one). It's also much more expensive compared to a netbook. No USB or expansion ports and needs a PC to manage most files. Apple is now also wrangling with a bizarre security issue with their batteries, of all things.
Netbook? Not as cool to have and play with, but at least it's all there. And usually around 100 gigs or more of memory storage. Mine was cheap and I'm very happy with it. I think if I go with another tablet, it'll be the Nook Color. Maybe the Samsung Galaxy.
In short, an iPad is more toy and a netbook is more tool. The iPad feels more natural (I think it feels great and don't regret buying it), and I can see how receptive people are to it as they bring it with them on their work breaks. The more serious crowd seems to prefer the netbooks. But the iPad is overpriced, as nice as it is.