The Mars 3x3 is the the debut 3x3 from SenHuan. It features an interesting design on the inner circle that increases the stability and smoothness of the puzzle.
I have not had too much time with this cube. It turns very nice and is smooth but stable. Mine felt a bit loose so I tightened it up a bit. However, it affected the corner cutting so I will loosen it back up a touch. Overall I feel it is well worth its cost and I definitely recommend it.