Villento has been around for awhile now but hasnt gained much traction with affiliates. The primary reason has been extremely slow or spotty stats and a lack of promotion of the program. They are a Microgaming operator, which is always a good thing and seem to be stable. A few people report decent earnings with them too.
Shark Casino used to be a fairly solid RTG operator but they have fallen on rough times and are going through a transitionary period right now. I wouls wait until they stabilize and move to their new software platform before I would actively promote them.