It's DRM-free, but visibly tagged with your name and email address on each page like other Manning ebooks.
Edit: This applies to the PDF version, the ePub and Mobi just put your name in the metadata, I believe.
As far as I understand the pre-release version is a regular PDF. I am unsure about the formats available when the book is complete, but I do not think that they were DRM'd in the first edition.
Yes, it is DRM-free, just uploaded to my kindle.
Does it look fine in a Kindle with E-ink?
I don't have JoC 2e yet, but I've read several other Manning books (including the first edition of JoC) on my e-ink Kindle and they looked good. You lose a little formatting and sometimes particularly wide tables or code samples get screwed up, but that's the nature of reflowed text and multiple target devices.