
Exped
MegaMat Series
Car camping comfort champ, but some side sleepers find it thin.

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Exped Ultra all the way. I have the 5R, mummy, and it is perfect for a side (and rotisserie) sleeper. (I do not find the mummy shape a barrier to comfort and it’s a lot lighter than the rectangular model.) Big Agnes’s Rapide is also very comfortable — I have the Q-Core SLX, the Rapide’s predecessor — but it’s true that it feels colder than the R-value would suggest. The Exped in my experience feels accurately rated. I use my little foam sit pad as a knee pillow, and be sure you have a high enough pillow, too. I slept comfortably this way for three months on my Southern Alps traverse.
The Exped pads are on a massive sale right now. A lot of them are out of stock but the Mummy 5R is in stock. TBH, at the current sale price, it’s probably the best deal you can get on a decent pad. I think it’s comfy enough but every air pad I’ve ever laid on has felt relatively the same to me. Some people have different experiences.
https://www.expedusa.com/products/ultra-5r-mummy I now realize that this sale may be USA-specific. I can only access the USA shop. I’m not talking about the Holiday Sale for 25% off, the pad I bought was a lot closer to 50% off. Not sure if it’s available at that price in other places, though.
Have the same and love it. Most comfortable pad I’ve owned
Exped ultra 3r and 5r. My lower back is bad, two blown out disc's in the same spot I have stenosis.
I have 2 Exped ultra 5r, warm enough for 3 season use in UK and haven't had any issues with either.
Vertical baffles (e.g. Exped Ultra 5R, now comes with 6.5R) work for me as a side sleeper more than horizontal baffles (e.g. Nemo Tensor). I use two thicker (4 in.) inflatable pillows, one for under my head and one between my knees.I used to use Nemo Fillo Pillow but it got too bulky to pack on a multiday trip.

Exped
MegaMat Series
Car camping comfort champ, but some side sleepers find it thin.

Exped
Ultra Series
Lightweight side-sleeper comfort, but a bit pricey and bulky.

NEMO
Tensor Series
Ultralight side-sleeper comfort, but slippery and prone to leaks.

Big Agnes
Rapide SL Insulated Sleeping Pad
Comfortable with side rails, but heavy and warmth claims disputed.

Therm-a-Rest
NeoLoft™ Sleeping Pad
Very comfortable, good service, but heavy and bulky for backpacking.

Ranked #1
Exped - MegaMat Series

Ranked #1
Exped - MegaMat Series

Ranked #1
Exped - MegaMat Series

Ranked #1
Exped - MegaMat Series

Ranked #1
Therm-a-Rest - NeoAir Xtherm Series