I've had the Klymit Inertia X Lite for about 7 years. It's their smallest, lightest pad. It packs down to about the size of a can of Coke. I probably have over 50 nights on the pad. It provides just enough cushion for a heavy sleeper like myself. Probably not a good option for finnicky sleepers, or tours where there will be rough or cold ground.

It's a nice option when size and weight is really a concern, such as a recent desert bikepacking trip where I had to go 163 mountain bike miles between water stops. Being able to bring more water, rather than more pad, was a good thing.

The bad thing about the pad is durability. I don't think I've ever gone more than 10 nights without it getting a hole. My ThermaRest pads have always been more durable, albeit heavier. I definitely wouldn't bring the X-Lite on a longer trip, or one where a functioning pad is a neccesity.

A few years ago I sent the pad back to Klymit for repair and they quickly sent me a brand new pad. Good customer service. But like phughes mentioned above, it had the new flip-valve. I find the valve to be horrendous. It leaks if I close it all the way, so I must gingerly close it till it's maybe 96% closed. The slightest tap with the valve cover can let all the air out quickly. The old screw valve was much better.

To summarize:
Good - lightweight and tiny option when space/weight is a concern. Good customer service
Bad - Durability. Flip valve. Not much cushion