...That is one of the constant questions writers (including yours truly) am constantly peppered with. I have done both in my time and have found, without question, the results to be more satisfying when I don't plan ahead and write copious amounts of notes about what might happen.
My reasons for this stem from the idea that since I write stories that are fueled by some kind of mystery or a MacGuffin somewhere in the novel it's much more fun if even I don't know what's going to happen. If I'm not sure what'll happen 20, 30 pages down the road, then it is a safe bet that the reader will have an equally hard time. The situation isn't perfect and it can lead the writer down unnecessary and irrelevant tangents, particularly early in the book, but at least the act is spontaneous and fun.
I also don't like outlines because I end up doing something different in the end anyways. Writing is more of a subconscious thing and when I tell the story I download the images and words I hear and see in that part of my head and put them on the page. In my experience, I get the feeling that I'm "trying too hard" to stick to some arbitrary idea instead of letting the story take me for a ride. I love that feeling when I'm reading a great book and I want to replicate the experience whenever possible.
Can you be a good writer and outline? Sure. James Ellroy, one of my favorite crime novelists, writes outlines that are hundreds of pages long for some of his books. He's made it work. In general, though, the authors I read and admire are ones who work from instinct and from the gut rather than some outline that's "supposed" to give them a great story. If you have faith in your skills as a writer and communicator, then the story you really want to tell will come out naturally without the need for something like an outline.