I've only used PT in two recording sessions, but I found it pretty easy to get to grips with right away. In many ways it felt like I was using Sonar 3.
 
The menus well laid out, and I didn't find myself endless searching through sub-menus to find what I needed.
 
It did come across as very basic in functionality however, and it seemed everything had to be done "the long way round", unlike Sonar/CbB which has a bunch of time-saving features. Even things like PDC had to be entered in manually (well at least on the version I had - I believe more expensive versions have automatic PDC).
 
I guess this is a double-edged sword: on the one hand, it makes the software much quicker to master (as there's less to learn), but on the other hand it takes much longer to get the job done when you get down to editing; although maybe this is intentional if the pro engineers are charging hourly!
 
One thing was clear though: it is WAY overpriced for what you get. At the time I thought it's only saving grace were the VSTi's that came with it, i.e. the AIR Music Tech instruments. However, I've since bought Xpand!2 for £1 from pluginboutique and upgraded it to AIR Complete for £59, so you're not really getting much for the remaining £100's PT costs.
 
In summary I'd say it's easy to use and gets the job done if somewhat in a long-winded way, but it's way overpriced.