My neoair basic early model is crinkly but with my sleeping bag on top, it doesn't bother me. It might bother other people who are more sound sensitive but compared to other sounds in the tent, plus just being so tired after a days ride has meant it's not been an issue. It's possible the newer ones are quieter.
Just remember trying one in a store will be louder without a sleeping bag on it.
As for r factor, whatever mine is (probably very middling) it's been fine in the temps I've camped at, lowest maybe 5c?
I have the NeoAir xLite and it has been fine for the occasional sub freezing night. I have been OK for a pretty cold night (18 F), but it wasn't winter so the ground wasn't all that cold despite the night time air temp. For real winter camping you probably want something warmer unless you supplement it with a thin foam pad in the winter. I think that I'd use mime with a z-lite pad if I wanted to winter camp.
It is quieter than my older original model NeoAir, but neither ever bothered me with the noise. When I camped with others they said it didn't bother them, but I don't move much while I am sleeping.