Dashes ("-") have a bad reputation when it comes to domain names. How many official domain names for big established products can you think of that have dashes in the domain?
I would guess that some see dashes as a negative.
www.experts-exchange.com have been around for ages, although originally without the dash to be fair.
Also, www.harley-davidson.com is redirected to from www.harleydavidson.com