I got the Jule Black Diamond with tapioca and 30% sugar.
The drink itself was just ok but the tapioca pearls were fantastic.
The atmosphere is nice and cute but probably not the place you're looking for if you want to sit down and study for a couple hours. Their menu has a note saying customers are not allowed to "loiter" and sit for longer than 3 hours.
I'd come back for a date or catch up with some friends but not for sitting down and doing work.