User blog comment:James12708/What we know about the Reapers and what I thought would happen in Mass Effect 3/@comment-24174486-20120814200132/@comment-1388547-20120815014556

Reaper hulls are presumably pretty tough, but under the concentrated power of Fifth Fleet, Sovereign falls pretty quickly once its shields are down. We don't have a good measure of how hard it is to take down a Reaper's shields versus how hard it is to destroy them afterward, but battle at the end of ME1 seems to suggest that the Reapers are like the geth: a lot of their damage-absorbing capacity is in their shields.