I bought these mats before and they lasted about 9 years - depending how much you roll your chair on it :) It was time to buy another one and it still has the same durable feel to it.
This chair mat protects as promised. Mine came perfectly flat when delivered so no "un-curl" time! The only issue I have is that the first time I stepped on it to sit in my chair the mat slid several inches and I had a nice little ride! Phew! I'm just more careful when approaching the mat.