I found the opposite:
Once your sheilds have been stripped one or two solid hits and you're a goner, the sheild boost allows you to survive an otherwise deadly situation once your sheilds are down, particularily useful on charging targets that get in your face.
Found that kind of play was way too situational for me to hang onto. AR, due to the time slow and when coupled with the huge damage reduction, saved me a lot more, not to mention the shorter CD. Fortification ended up making me highly vulnerable with a CD that lasted too long, and it would still get stripped too easily.