Virtual-Hideout posted a review on the Razer Mantis Gaming Surfaces

If I could change anything about the Mantis "Control" and
"Speed" I would either make them much smaller, or much larger. For high
sensitivity gaming, where you don't need much movement, so why make it so big? If it were bigger, enough that I could fit my keyboard onto it, I think it
would also solve the space problem.

Razer Mantis Gaming Surfaces Review