I am kind of a fan of the Princeton physics in a nutshell series. The first one I bought was Tony Zee's Quantum Field Theory in a Nutshell. I've bought five more in the meantime, including one electronic version (Einstein Gravity in a Nutshell, also by Zee).
The thing is, I kind of like the way the matching covers of the other four line up on my bookshelf. I don't find electronic textbooks easy to read, though Princeton's books seem better than those from Cambridge. So anyway, is the extra two hundred pages in the second edition of QFT worth it, especially if I consider the added benefit of the matching cover?