Depends on the guy. The immature ones won't like it, but you don't want those types. Anyone who's mature, has a sense of himself, has nothing to prove, and appreciates honesty will definitely find it a Good Thing.
Of course, phrasing things the right way helps tremendously. Tact is better than nasty.
Nine times out of ten...no. Unless you're already a part of their life. I mean I know most people are going to be all "Yes, they do! They love an outspoken woman" but it's not something I find is true. I find that when a woman speaks her mind and knows exactly what she wants and how to get it that the men in her life no longer feel needed and it becomes a power struggle. It takes a really strong man to appreciate a woman who doesn't hold back.
I shoot straight from the hip because I'm tired of guys stupid games is this a turn off?
My husband loves it. He loves that he doesn't have to read my mind. He knows when I am upset and what I am upset about because I tell him. It makes the bedroom more fun too because I say oh try this or try that. All around it has been great for our relationship that I say exactly what I think.