I have two machines. The Resmed 11 is great.
I bought an AirMini to travel. When you are out of your Timezone the AirMini does not show the correct hours it has been used at all. I contacted Resmed, and they said that was normal. For a machine designed specifically for travel!!!
It did update correctly when I got home, but, if you are staying overseas, the details that doctors need is not correct. This is extremely poor. I would not buy the AirMini if you need to report usage whilst overseas. What a ridiculous oversight.