I use them a lot, actually. Because Jana is so socially awkward, my pre- and mid-sentence ellipsis are usually when she's trying to find the right words to something. At the end of a sentence, I usually have them there to indicate when she's not just trailing off, but also leaving something unsaid (either out of her general discomfort or because she simply couldn't find the words). However, I never actually use "..." as a statement in itself. If Jana's silent as a response, I'll usually specify if she's being silent because she has nothing to say or if it's because she's, again, uncomfortable and can't find the right words.
