I can't agree. What's revolutionary about the iPad? Only that isn't running a desktop OS? There have been Windows CE tablets for ages. The difference is realization, which is everything, of course, it's the difference between Altavista and Google. The iPad will be successful But revolutionary?
On other side, you have the first device that it's at the same time, a tablet and a eink reader. I don't know if it will be successful, probably not at the same scale, but certainly it's much more revolutionary.
Anyway, if anything, I think this device could hurt more Kindle sales than iPad ones.