Sufficient, but could be stronger.
I've really given this machine a good and thorough testing. The sensation is absolutely amazing. However, I docked it 2 stars due to the motor not being strong enough for hard anal. When the sensation hits hard, the motor can't push hard enough back and it shuts down causing me to stop and reset. This happens more as diameter of the toy increases. Also, it moves around too much. Suction cups to hold it in place would be beneficial. More selections of bigger diameter toys would also be great. I am way past the smaller dildos that accompany it. Bigger Vacu-lock toys aren't easy to find.