I mostly work with micro-sites and parked domains so I know that if I didn't use hyphens I would miss out on a lot of quality domains. From testing out domains with and without hyphens I haven't really seen it affect its rankings.
I'm guessing you are looking at a scenario where not using a hyphen might give the domain a different meaning than the one you intended. I would go with the hyphen
I'm guessing you are looking at a scenario where not using a hyphen might give the domain a different meaning than the one you intended. I would go with the hyphen