I usually present in person and don't have any huge pain points around doing it this way. I think tools like this that allow for comments to be left on a mockup

I usually present in person and don't have any huge pain points around doing it this way. I think tools like this that allow for comments to be left on a mockup is interesting but not a deal breaker: http://redpen.io http://redpen.io I use Dropbox the most to share files with clients. Recently I've been working on a concept for presenting mobile designs - I think this process is more broken than other types of design presentations.