dashes is one of those things that you have to make explicitly known, and more than one I would say is a bad idea. If you are telling someone about your site, you will have to make sure you say "Planet DASH Dugan.com". You don't want a visitor to your site to end up at planetdugan.com. I would say that as long as you make sure that the dash is very clear and understood, then I don't see too much of a problem with it. The example you provided seems ok with a dash, but again, as long as your visitors know about it
Edit note: feeling redundant because I posted about 30 seconds after dannybedor.