This is a nice addition to our arsenal when traveling or meeting with clients. Although it may have the some very advanced features that are key even in a small form factor kind of tablet/screen like this. It does not match up to the same working experience and real estate that you would have when going with a Cintiq 22" model:
http://www.wacom.com/en/us/creative/cintiq-22-hd
I know that you stated that you had another monitor that you could shift the menus over to. The ideal factor to consider is comfort and easy execution with the projects that you are working on. I love the fact that when my team and I have to work on the 22" model, we don't run into the feeling of working in a cramped work space. I want to be able to access the details of what I'm working with while still knowing that I don't have to drag over the various areas of my projects repetitiously. That's a comfort factor for me.
You may not need to worry about all of that. If you want something that will allow you to just get in and start working on your project. Then the 13" model is a good one to go with. Especially for it's portable features. I would go with the Cintiq 13" HD model:
http://www.wacom.com/en/us/creative/cintiq-13-hd
That model is equivalent to the screen of retina display on a Mac. The images and color are sharp!