As a new DBA (<1yr), this book is my best reference guide. Some of the early concept parts I can do without, I prefer the concepts guide for that. The most valuable parts for me were the parts on the configuration and setup of the tablespaces, along with the backup and recovery implementation. From my read-through of the tuning material, I'm sure the tuning sections will be helpful when I get to that point. This book is not just a reference, there's a real focus on how to do things with a process-based focus.
I'd like the next edition to cover OEM instead of just focusing on the line mode commands. The line mode commands show you all of the details that OEM goes through, so that's useful, but I'd like to see the screen-based methods as well. That way the book would be even more useful for beginning DBAs.