No Engineer should be without this. It will seem weak early on, but you will see its benefits very quickly. Save all of your Charges for this ability, as each charge will increase the amount of damage absorption by 50% per Charge. Early in a battle, if may difficult to gain enough charges to warrant an effective Forcefield without taking massive damage, but once this ability is up, you don't have to worry about dying. Keep this up as much as possible. Max this skill out immediately.