The only real way is to evaluate for yourself. I'm sure both have their pros and cons. Personally I like Protean too much to move away from it - however it does irritate me when I try to move the cursor during an 'intellisense moment' - it sometimes screws up my cursor. I like the way Protean handles my projects and folders - very easy to add stuff in bulk and rearrange things. Not tried IDEal (there's only so many IDEs you can try).
The IDE I use at work (Visual Studio 2005) is fantastic and never annoys me.
The IDE I use at work (Visual Studio 2005) is fantastic and never annoys me.