Hyphen sites are good only for one purpose... well 2. One is for SEO and the other is to rip off traffic from the real url.
example..
gofuckyourself.com some ass would buy go-fuck-yourself.com and then only use that to catch people searching for it on google. I deal with these morons on a daily basis ( i do seo and cpc).
i wouldnt buy a hyphen site, unless you are tying to promote something like
www.free-colllege-term-papers.com or some bs like that. think about the people when they type in the domain. you dont want to say, he check out blah HYPHEN blah.com