I have recently traded my slightly old and bulky thermorest for a new sleeping pad, the Pacific Outdoors 'peak elite ac'. I have now used this camping quite a few times now and I'm pretty pleased with how light and compact it is as well as being comfortable to sleep on. The main advantages over something like a self-inflating mattress is how small you can roll it up. Once packed the pad is roughly 10 cm by 30 cm which is much smaller than my 4 season thermorest which took up about a third of my 50 litre backpack. Inflated the pad gives you about 7 cm of air core cushioning (2.5. inches for my american chums).
Along the main sleeping torso area there is a Radiant Heat Return technology that apparently increases your R- value my 10 % giving you a rating of about 3 seasons. Another nice touch is the super light anodised aluminium values that look pretty robust and durable. In summary, one of the best pieces of outdoor gear that I have bought this year.
The regular sized pad is 396 g in weight and has a R value of 2.5 - 4.4.