Different level of difficulty of Casebooks: Yale vs Duke

I´ve been preparing for McKinsey and I've been using a lot of Yale Casebook 2013 since it has a lot of McKinsey-style cases, but recently I felt the cases in this book are a bit simple and one-dimensional.

Then I started with Duke 2015-2016, I felt cases in this book are quite long and difficult, it could be around 6-8 pages and 3 exhibits. Do people really solve these cases in just 30 minutes?

So I wonder: what´s the difficulty level of cases given in real life interviews?

Also shout to Experts: in your opinion, which casebook offers the cases that are the closest to real life interviews?