I have made several bets now on Gulden.bet without any troubles. It's very easy to use with my android Gulden wallet.
In a few steps you can make your bets:
1. Choose your match and decide which result you want to bet on
2. Choose your betting amount
3. Fill in your pay-out address
4. Choose if you want to receive an email with details of your betting
5. Push the next button and a QR code appears
6. Open your android (or iOS, desktop) wallet and scan the QR code and hit the send button
7. Gulden.bet send you emails with the betting details and a email with the paying details
and now you can wait for the game.
Also the payout was fast, within a couple of hours after the match ended.
I have made bets in total for 42.000 Gulden and won 45.370 Gulden, so a small profit, But that was not due to this nice betting site
And when you run out of Gulden you can easily buy new ones at
https://nocks.co/ where you can pay with bitcoin or Euro.
Also you change back there your winnings to Euro or Bitcoin.