I recently picked a great book: Pragmatic Version Control using Subversion by Mike Mason. I have previously used both CVS and VSS. I never administered either one, I just trusted them to do source control for me. My teams always had a version control resource; therefore, the most I ever really needed to know was how to check in. Do you care? Probably not, but it gives you some context as to my level of experience with version control previous to reading the book.
Now that we have my background covered, on to the review. I really enjoyed the book! Mike manages to cover the important (and sometimes not so important) functions that Subversion offers while holding your attention the whole time. I found the book to be easy to follow and it provided good examples in both Windows and Unix. By following the examples I had my own repository up and running in no time. After reading a few chapters I felt comfortable working with Subversion and would have no problem using it in a professional environment.
So the book is great, but what about Subversion itself? Well, the short answer is, it's great. They fixed several things that many developers felt that were missing from CVS. Additionally, the staff that helped create Subversion were almost all CVS experts. Therefore, if you are comfortable using CVS the jump to Subversion should be a very easy one. If you are stuck using VSS, the jump is harder, but even more worth it. The software is free for download on the Tigris site.