Can concur ~ Ultra lights mats like neoair are noisy, Exped lightweights although rated in the UKC gear test are not that robust, Closed cell foam base to a sea to Summit does make a difference.
Are you a side sleeper? if so the sea to summit probably doesn't quiet have enough support / thickness.
I have the same problem, perfectly comfortable, but rarely get a good nights sleep, though can't quiet figure out why. Tried both sea to summit and expeds, with similar outcome, but found sea to summit to be slightly more comfortable.