Well...I "tend" to think that long domain names with hyphens are more used by spam sites...but this doesn't mean that SE will treat ur site based on that unless ur content is really that bad; check this article:
http://www.guruofsearch.com/domain-name-with-or-without-hyphens
Please note that, search engines always try to think like the "users" to improve the user experience obviously, so don't ignore this point.