The only problems I have with the Logitech M570 are that it's bigger and it is only designed for right-handed users. The Kensington is smaller so it fits more easily in a bag and it doesn't matter if you're right or left handed.
If anyone has experience with this classic MS Trackball explorer how would it compare to the reviewed model? trackball explorer 2.0 - Bing Images
I recommed this to everyone I can, I have 3 right now but I know they will not last forever. Thanks Josea