I went through a fretless phase a few months back. There are some amazing fretless players, but to me the tendency seemed to be to either play shreddy stuff, which sounds exactly the same as on a fretted instrument (except with the added marvel of the guitarist's ears), to play "exotic" sounding stuff, or to play what basically amounts to slide guitar. The latter two genres don't really appeal to me, and in the first, the instrument actually seems almost to be an impedement to the artist, if that makes sense. Personally, I would love to play around on a fretless, but my ears aren't nearly good enough to have any real success creating music with it