Absolutely terrible!
Avoid this service (if you can call it that) at all costs. First they charge you a small sum, and then in the fine print they write that they'll charge you 299 dkk monthly after two weeks. Of course, as the evil people that they are, they won't remind you of this so when you see -299 DKK in your bank account, naturally you get a shock.
I emailed them the same day as I saw this fee, and said the truth; that I had only used their service once (the very first day) and that I would like the remaining money back (27 days). And they answered "we can't do that". I get it, you "can't" because that's how you earn your money, by fooling consumers.
Avoid them. Use DBA and Facebook instead - a lot more realiable. Also, on DBA and Facebook, the apartments that fit your interest don't disappear the moment you click on the link. Boligsurf on the other hand, puts out these fake ads all the time. They look great when previewing them, but when clicking on them - whoops - it doesn't exist.