I brought my ms to both conferences I attended this year. I brought it because I had done the "advance submission" option, where conference attendees could send the first 20 pages of their ms to an editor or agent advance reader.
I sent a portion of my ms one month in advance to an agent, then met with the agent at the conference for feedback. At that conference, b/c there was interaction b/w agents, editors and writers, it made sense to bring the ms.
In any case, I say always bring the ms. It will be there if you want to work on it if the inspiration hits and conferences also may have "read and critique" sessions where you will get a chance to read it aloud.
Debbie