They are essentially the same vehicles. body panels are different, and for 2014, I think the compass has some changes done to the gauge cluster to make it look "upscale). But mechanically, they are the same.
The body panels you'll notice slop in more at the top on the compass, where the patriot is more square, so for broader people, and for stuff in the back, there is just a bit more room in the patriot than the compass. Not much, but I noticed it sitting in both right after each other at the dealer.