Milking robots are spreading throughout the Canadian dairy industry, although with the two main suppliers, Lely and DeLaval, there is some controversy whether which robot is better than the other. The majority of people I have met are partial to Lely robots because they use the much quicker brushes to clean the teats rather than the cup style that the DeLaval's VMS uses. Even though the VMS is a great machine, I personally do not think its performance out weighs that of the Lelys.
To learn more about the pros and cons of each robots performance go to:
http://www.dairyforums.com/forums/showthread.php?3065-Lely-vs-DeLaval-VMS
i would think the brush style would hurt the cow a lot more since the brush looks pricklier and with a cup it would sit over and it wouldn't hurt the cow.