The heft and weight is nice, when I got to handle one, and the epaper surface is very neat. Page refresh is slow, and the blank before rewrite is annoying. I'm told that Sony has fixed that problem with theirs, so Amazon will probably roll out a similar fix.
I don't buy v1 of things, especially consumer electronics, especially something with that much software, under the hood IT, and DRM.
And $400 is too much.
At $200, I would be more inclined. Even if it was $300 with $200 of Amazon store credit, I would still be more inclined.
If every physical book I buy from Amazon in the future would also appear on the Kindel at the same time, I would probably buy it in a few months, after the shake out.
If every book I've bought in the past from Amazon would appear on it, I would probably buy one in a month.