The in dash units fall apart. Why bring that on yourself? If you are worried about theft get something to lay over the screen dont buy an over priced and likely to break motorized LCD...
Here is a link to my install thread...sorry it is the same as usual. But sometimes there is value in that.
In dash may be easier to install, but it will never be as good as a solid mount like that.
The in dash is really the standard in that you don't need to do anything more than take out the stereo and mount two boxes back in, but the screen will inevitably be in the way of something.