My answer to your question would be no. The self inflating mattresses are pretty good, much better than an air mattress, but you'll know you slept on one in the morning. You didn't say whether you'd be packing in or just driving up to a campsite, but if your driving, or the hike isn't far, a good cot with one of the self inflatoring mats will do wonders for quality of sleep.
If you do decide to get a cot, check around and see if you can find a GI issue, not hard to do at all if you're anywhere close to a military base, just check the pawn shops out.