I saw Bourne Legacy over the weekend. As a general action flick it was fun.
If you're looking for continuity with the first three, not so much.
In the first ones the protagonists search for his past and the meaning in it gave it focus. In this one that isn't even part of the story, now it's just a hunt for the next fix. (Won't add anything else that would be a spoiler, that much can be gleaned from the trailer).
Great mountaineering photos, shooting stuff, blowing stuff up, and a good motorcycle chase make it fun escapism though.