The iPad, feature wise, is rather mediocre. What tips the scales heavily in the other direction, however, are 2 things:
1) the 10+ battery life 2) and perhaps the biggest factor, it's excellent UI
To a smaller extent, the application development momentum.
The above, Apples fanatics, and the fact that next gen competitive products have yet to hit the market, makes it look like a grand slam. I think it is a great product, and by any measure, will succeed. But it will carve out a niche market, I think. It will not take over.