I've taken a respro sporsta mask to BurningMan two years in a row. It works great for the very fine-grained dust out there, but is much more stylie than any other HEPA option I've seen. The neoprene makes it take up minimal space, and the velcro on the straps provides a bit of adjustment, making it easy to keep it around one's neck when not in use.
It's not easy to be understood if you're talking through it, but it's easy to breathe. The valves work well for exhaling, and the seal ensures that you're only breathing through the filters.