Upshot: A great survey of HTML5, relevant examples for all levels. Good documentation of the gotchas, too. No downsides, other than it’s in draft right now.
Even though HTML5 Cookbook is in early draft — seriously, the Introduction is still a template —there is a LOT of good stuff here. If the priority with the authors was to get to the meat first, then they have executed on this very well.
As it is, this book is an excellent companion to HTML5 Up & Running, providing even more examples & gotchas, although perhaps without as many backstories as the former book. This is a cookbook after all. Though, when you get into Geolocation, Web Workers or Canvas it might be good to also have dedicated books on the subject. It goes without saying that I recommend that you purchase this book directly from O’Reilly so that you can (1) read it from any device, and (2) so that you can search it from your desktop machine (how you’ll do this on Windows is beyond me, though there are now solutions on the Mac side). Even in draft form (as of this writing) it’s still quite readable, as is the case with most ORA eBooks ‘in draft.’
Did I mention that O’Reilly is probably the only publisher I’d buy a draft from? Highly recommended.
Disclosure: I received the eBook download(s) from O’Reilly for review purposes.