Almost all contests held by Roobet here in Bitcointalk has been successful, the focal person of these success is probably because of the guy who manages all these things, Hhampuz. Personally I always like of what they come up with. Also, I miss their free-participation games which was held here before.
They have creative idea to do their business. If you have marketing budget but don't know how to use it effectively, you will not get good result from your marketing. Roobet team did their great job by spending big fund for marketing and hired a perfect manager Hhampuz for their marketing campaigns including contests.
With good prize pool, they have great chance to attract best applicants and make a lot of noise in and beyond forum. It is how marketing works and makes domino effects. Roobet is a first casino I knew that they run different contests from art designs to their game challenge. Together with their signature campaign, their casino does have very good appearance and noise in Bitcointalk.