I'll give you a bit of my experience. I had the site overseas-property.ie. This worked brilliant from an SEO point of view, managed to get to the top spot for "overseas property" in all the search engines at one time. The problem came when trying to market it through word of mouth or over the phone. People would forget the hyphen all the time. Sure you can always 301 it afterwards but think about all the marketing you've done originally telling people the domain name. I'll never go for a hyphenated domain again. I had to go for it like you as overseasproperty.ie was already taken. Stay away from hyphenated domains for serious projects.
I actually put it more down to link building. As long as you have a keyword rich domain name (hyphenated or unhyphenated), it is easier to get links accepted using these keywords as it is the sites url. An example would be mortgages.ie , directories will accept the page title "mortgages" as it's their url.
That's a very valid point, but I did test before link building and Google was returning better search results for the domain than for the keywords which had been crafted in the content... that's not to argue with you, just to supplement your point