Guitars in general have specific advantages such as the abilities to play full chords; widely spaced harmonies; simultaneous bass, rhythms, melody and harmonies, natural and "artificial" harmonics (allowing harp-like passages); and so on. Their principal disadvantage, relatively low volume, is eliminated by modern amplification.
I've had little use for steel-string acoustic guitars, although I've written a piece for one particularly beautiful instrument, and play mostly (and, a minor specialty, compose for) finger-style on classical, which I genuinely enjoy. That said — when I play my slightly modified 1980 Ibanez AS200 after it's stood idle for awhile, I'm often struck by how gorgeous it sounds. So, while I enjoy my classicals very, very much, the steel-string electric AS200 is my favorite.
EDIT: Two responders were downvoted for their "violin" preferences. As that's obviously ridiculous, I've upvoted both to compensate.