G'day Sam,

I have this mat & have no issues packing it away.  Carry bag has a synch chord so the bag can be expanded and contracted as needed.
For all double self-inflating mats we recommend doing a rough roll to push as much air out first, and then do a second roll when the mat is already semi-deflated and easier to manage.
This is not specific to Sea to Summit, and is best practice for any brand.
If you are wanting to go with a pump option, we recommend the EXPED Mega Pump.

G'day Stephanie,

You can use this in a Rooftop Tent and you can pop this on top of the existing mattress or take it out, up to you. It is recommended to pack it away each time and not close a self-inflating mat up in a Rooftop Tent as it could damage the mattress.

G'day Lisa,

Sea to Summit has a dedicated Sea to Summit owned, operated, and managed factory in China.
Other brands will approach an already established factory and ask them to make more generic gear, but thats not the case with Sea to Summit. Everything is designed and manufactured to exacting standards, controlled by the S2S team at every stage.

G'day Josh,

It's a hard one!  They're both pretty fantastic mats, coming from high end, reputable brands.
Sea to Summit are traditionally known for lightweight adventure/hiking gear, so their Comfort Deluxe is only fairly new - maybe around a year - when compared to the Exped.  I think in terms of popularity, that is largely due to the fact that the Exped name has dominated the market for such a long time.
Having personally laid on both, I find the Sea to Summit slightly more comfortable, but I am aware that comfort depends on the individual.
We have a few great reviews on the single version of this mat, so I'd say whichever one you choose you'd be happy.