I've already read Combating Cult Mind Control, Crisis of Conscience and Apocalypse Delayed.
I picked up In Search of Christian Freedom about a month ago. I'm about 430 pages (12 chapters) into it so far, and I've got about another 300 pages to go. It's been an enlightening read so far. Not that there's been a lot of "new" there that I didn't already know, but Franz's countless examples have helped me see the big picture a little more clearly.
Crisis of Conscience was half memoir, half Watchtower critique. It was also half the size of ISOCF. Franz still had a lot to get off his chest, and he does so in his second book.
What has really stood out to me is the countless of examples of double standards that have been applied throughout WT history. The picture that emerges is one of a religious organization concerned first and foremost with glorifying, protecting, and strengthening itself. Religious doctrines, policies, and teachings are then massaged in accordance with this primary goal. Of course, I had suspected this was the case for a very long time, but I have never been in a position to be able to verify that with my own eyes. Ray Franz does the filling-in for me and leaves no doubt that the WT was and is a religion, like most other denominations, interested in solidifying its ecclesiastical authority over its followers first. The well-being of its "rank and file" members is more of an afterthought.