I haven't used DP for ages, but what I hear from friends is that there are some key features that are not available in Logic. However, that is true when switching from any app A to app B. You just have to make a pro/con chart and see if there are any deal breakers.
Logic always gets a bad rap for its steep learning curve. The main reason for that is that it has so many features to learn and most importantly, its open object-based structure. In my opinion, this is the most powerful feature from a power-user point of view because you can customize so many things. When you work with with it every day, you really start to appreciate it. For a seasonal user, this might be overkill.
There is one important aspect about learning an app. It is often more difficult to learn a different app, that it is to learn a new app. You have to unlearn concepts and workflows which sometimes appear strange at first. That's why it is very important, for example, not to find where the new Record Button or Play Button is, but discover the many different actions that happen when you press those buttons and where to configure them (and knowing that you can configure them in the first place).
As I mentioned, the different concepts and underlying architecture is the most important thing to wrap your head around it. I wrote a manual in my Graphically Enhanced Manuals (GEM) series, "Logic Pro X - How it Works", that explains those concepts with lots of graphics and diagrams that are not found in any other book or tutorial. I discuss and illustrate the various topics in great details, providing all the various commands for specific actions, not just one, so you can choose which one suits your workflow best.
One more thing ...
You can download GarageBand X for free. It is based on the same code as Logic Pro X (it is actually the new Logic Express). Although, most of the advanced features are not available, you still can get an overall feel for the app: layout, color codes, terminology, etc.
Hope that helps
Edgar Rothermich
http://DingDingMusic.com/Manuals/
'I may receive some form of compensation, financial or otherwise, from my recommendation or link.'