So, this is the deal with them:
Citing from e-mail support:
...we use multi-signature wallets to keep your bitcoin secure. The trade off is that network fees are larger than what you may be used to paying for other transactions, but I hope you can appreciate that we put security first.
In essence, minimum transaction fee can be set to 0.0016 BTC (currently $3.79), so be aware of that when you plan to use their service.
Beside this, I had only good experiences with them, so you can say it was my mistake.
And to mention, every support ticket was answered under a minute!
You have great service guys, and I really appreciate your enthusiasm to bring this service to our community, but this fee will kill you in long run.