There are only two differences between a demo key and a referral key. First, a referral key will allow you to start with a friend on your friends list. (Demo and referral players can't send friend requests.) Second, using a referral key will help out a community member. (There are bonuses available to those who recruit. To see what they are, go here:
http://www.startrekonline.com/referral)
So, please, if you are already going to demo the game, why not get referred instead? You still get your demo, you get an in-game friend, and you help out someone in the community you with to become a part of. Everyone wins.

Earlier today, I decided to try to acquire the Dreadnought through the referral program. Not knowing a lot of people who would be interested, I was left with asking the community if anyone would be willing to help. No matter how I put it, I hated how selfish it made me sound, or how it made me sound like I was begging. So, I decided to make a plea for the entire community.
It doesn't matter to me whether or not you ask for a code from me, but if you plan on demoing the game, please ask the community for a referral key instead of using just a demo key. You'll make someone's day and get something slightly better than you originally planned.
But, what if I already acquired and used a demo key, you ask? No problem! As long as you haven't yet applied a retail key to your account, you can still ask for and use a referral key, and make a community member very happy - and at the same time, make a good impression on the community you are joining!

And here's a tip, as a good-faith gesture on behalf of the entire community: Amazon has the Collector's Edition available for $7, and the digital download version for $2.50. No joke, no gimmick. You now have nothing to lose and everything to gain! Ask a community member for a referral key today!