I believe the best out there is the Martelli mat....You can order from their website (
www.martellinotions.com)..some :QS carry their stuff - and they are vendors at many of the larger quilt shows.........You can even iron on their mats......I have destroyed several of the Olfa mats ( and they were not cheap ) and I have not had any digs or groves occur in my Martelli mat that I bought 5 years ago! None of the Olfa mats ever lasted that long..............