It can be depressing, and often they seem to consider things that are outside of their remit, but the process is worthwhile/important. I went to MREC for my project, a week later I received a list of over 50 recommended changes, ugh! Some were fair enough, but there were a number that I didn't agree with, so when I submitted my changes I didn't change those things, but sent a letter justifying my decision. They didn't argue any of those points, so it's worth keeping that in mind.