Edited to add: we have had this 2 years (roughly) and it is still very durable and great for practicing! Her tumbling has gotten more advanced and thus she's fallen more. It still absorbs her falls well!
My daughter is a competitive cheerleader, but at 6 years old, she is still learning the tumbling fundamentals that go with the cheer world. After receiving multiple referrals to this mat, we decided to spring for it. We went with the 1 3/8 in, because again, it was suggested to be the better of the two. The 2 in (although it doesn't seem to be that different) is said to be not as firm, and firmness is needed in tumbling. First, shipment was crazy fast. We ordered on a Saturday, it was here Monday morning. It is easy to maneuver around. It is big enough to do any standing tumbling on, but small enough to easily store. The quality is insane. It is very different from the cheaper versions out there---you can tell this was made to stand the test of time. I also love that it has the ability to be safely and securely attached to other mats to make a longer tumbling track (which is perfect for practicing tumbling sequences). If you are worried about safety with the 1 3/8, my daughter doesn't always land her tumbling, and has not been injured nor said anything about it hurting when she does "fall".