When I let others read my work-- my wife, my critique group, my agent, my editor-- I am always as open as I can be. I always listen to their thoughts and criticisms. I reread comments several times. People can help you make a better manuscript and I try not to let my ego get in the way of that. I want the best manuscript I can create and I’ll take help wherever I can get it. Readers help. Good readers can really help.
That said, some people will try to make specific suggestions for changes. They will try to tell you HOW to revise. What I mean is they might say that X in a certain scene bothers them. They might suggest that you do Y instead and give you a detailed explanation of Y, of what you should do to fix a scene. It is very, very helpful to know where people feel something is wrong in a manuscript. What I listen to less (very little, in truth) are the specific suggestions about how I should fix a scene. Usually they just won’t work. Usually, these need to come from me. My advice is to listen carefully to X and be grateful but be suspicious of Y.