I am reading Princes now, and it has me really excited to run it. I love the sandbox nature of it, and I think my players will really enjoy it. However I don't think it's all the reviewer has made it out to be. The organization is pretty bad in the book, and you need to read it a few times to get a good handle on whats going on.
Lots of people aren't going to be into it either because it's a massive AP, despite the fact that it can be broken down into chunks, and actually has a lot of independent side quests.
I read another reviewer who slammed it for being hard to read, hard to run on the fly (due to the lack of chapters/milestones), etc. I don't agree with this assessment, but for the time poor DM (or one who can't be bothered reading it end to end before running it), it's not going to be their cup of tea.