The bonus I've taken about two times now is their monthly reload of 100%. The reason I like it is very simple- it gives 100% match for a deposit of 20€ or more and the wagering you need to meet is only 40x bonus amount. This bonus is available for the first deposit of the month and even if you decide that you don't want it, you can cancel it at the cashier, also the cashier is really simple and you can see your wagering there, it's something I really like.
This month I used this bonus too and deposited 25€ and received a match. With that I had 50€ balance and needed to wager 1000€, which is 20x the balance amount and I consider it to be a good deal, because many casinos with Netent games offer only 50% monthly reload. I made this deposit using Skrill ewallet but overall they have many banking options.
Having 50€ balance I started to play Twin Spin slot. At fist I was having some luck and had a few big winnings that helped me to get my balance up to 80€. Then I started to get a dry run and went to play Koi Princess. Game was in a bad mood and since I was playing with 0.40€ bets, I lost 1/3 of my balance really fast.
My game play continued with Flowers slot, Starburst and Gonzo's Quest but in none of the games I managed to increase my bankroll and at the end I lost all.
Overall I do recommend both this casino and this bonus, because the variety of games you can play with it is large and support is very good too, lobby looks nice and wagering is quite friendly.