As a general rule its best to go for the shorter name if it's a meaningful one, but choose the longer name if it's easier to remember. Don't make the mistake of choosing some ‘long winded name' that may name your business but is easy to forget and even worse, easy to mistype.
From what has been said it should be clear that your customers remembering your domain name is very important from a marketability perspective. Remember, people have to type the domain into the address bar. How many times have you typed in a long winded or complicated domain name and got it completely wrong? It's happened to us all!
Domains that are household words, easy-to-remember phrases, or keywords have the greatest value. Who is going to be able to tell their friends about your great site if they cannot remember the name of it? To find your site again, people have to remember how they found it the first time.
It really comes down to one simple tactic. Just remember to make the domain name memorable. Your company's domain name is its online identity. Think about it like this. Would you remember it after seeing it just once? Hyphens tend to be a ‘no -no' for that very reason. People forget where to put them.