So I've tried unbreakable and for the most part it's decent, it's spread thin trying to fit in all the parts of sentinel so much that it's meh. It gives OS for offensive bulwark and barely does anything with controlled demolition, doesn't really fit with bastion, don't get me wrong though in PvE it's great and does it's job perfectly, but in PvP it's pretty much a poor man's pocket singularity that deals even less dmg even if you filled the bar for it.