If you are ranking well for more than a year , you'll be effected really really bad , I think there was a redirection for this to pass the strenght of your site to the new domain.(I remember it to be redirect 301 but have look).
But it would be risk.
I have a catched domain the owner dropped cause he bought keyword1keyword2.com and my domain is keyword1-keyword2.com and I am ranking on the first place on google
There are more than 200 factors for ranking in google search the redirection method carefully.