Today I also got preliminary feedback on Trust from one of my beta readers--he was confused about some things (he hasn't read Trang--I told him not to because I wanted that perspective), and he had some suggestions for improvement. At this point I know my initial reaction will be all ego-y and "My deathless prose!" so I just don't think about it, and an hour or two later when I'm, like, making lunch my subconscious serves up a bunch of fun and exciting ways to incorporate the suggestions into the book.
I think there's a real art to taking feedback--I worry about the people who just change and change and CHANGE AND CHANGE things. At what point does it stop being your book? And what happens if you first give your manuscript to an adrenaline junkie, and then give it to someone who loves to unwind with poetry? Do you just make a million changes on Tuesday, and then unmake them all on Wednesday?
But on the other hand, feedback is something that everybody (even Joss Whedon!) can use. My feeling is, it's about knowing what's vital to your story, so that you accept what will help and reject what will hinder the telling of it.
Dean Wesley Smith argues that "Work-in-progress workshops are death!!!!!" (bold in the original, oh, yeah), and I have to say that I've seen people try to write and workshop at the same time, and I don't think it works. I feel like the problem is that they haven't sorted out what their story is yet, so how can they possibly tell if a suggestion is going to help or hinder? It's a little like gardening: You have know what's planted before you can figure out how to make it flourish, because a cactus is not going to want a lot of water and rosemary does not like fertilizer.
Sometimes it take a surprising amount of time to figure out what your story is, and a workshop or group can help if someone says, "OK, your story's about X, so focus on that." But I feel like once that is said (and the writer goes, "A-HA! That's exactly right!"), then the writer should just pack up and go home to revise. I think when people get insecure and start accepting everything, they forget that writing is, at the core, a solitary pursuit. You have to overcome things like plot problems on your own--and with any luck, you'll figure out a really cool and unique way to do it!