If this is legit and DRM-free, yes, there are a few books in there that are worth reading. I own hard copies of:

* Hadoop: the definitive guide

* Cassandra: The definitive guide

And they are both excellent books. I have heard good things about:

* Think Stats/Think Bayes

* Learning Spark/High Performance Spark

EDIT: I just bought the bundle. The PDFs seem legit and DRM-free -- O'Reilly no longer offers DRM-free ebooks, so this is useful.

Just a note that Think Stats/Think Bayes are available for free on the authors website: http://greenteapress.com/wp/

Is this a good book to start with?

It's designed for teaching statistics to people who are already proficient at programming. I learned statistics first then learned programming so I can't really say from experience how good it as but I like the examples and the writing is clear.

Humble Bundle content is DRM-free. Once you pay you get download links in your e-mail for downloading the content. Books are offered in PDF, ePub and Mobi formats. You can back up the books and/or keep the e-mail for future.

If you sign up for an account you can also save your purchase to your account and then access all the purchases made through the library.

Humble Bundle is, indeed, legit.

I have R in a nutshell. It is a pretty good reference but maybe a little brief and outdated.