I've ended up with 3 mats, 2 self-inflating and one that has to be inflated, which is the one I like best. I started off my hiking career with a blue closed cell, hated it, couldn't get comfortable at all. I now cut it up when I need a new sit-on mat.
For me personally, I've learned from experience that after a long days hike I need to rest comfortably. I also sleep on my side which for me is one of the reasons why the blue closed cell was so useless, my ilaec crest bone was always so painful by the morning.
One of my self inflating mats, they are all Thermalites, is 'old,' about 6' x 2'.52 x 2" thick and I use it when we have visitors, its ideal and very comfortable. I'm always up early and prefer to sleep downstairs so that when I'm up and doing, the visitors can carry on sleeping and I don't have to disturb them.
My other Thermarest is a 4' x 2'.5" x 1" thick Prolite. I bought this one to save weight, in hindsite, daft! I wish I hadn't spent out my money on it because my feet overhang the end, (I use a piece of the blue mat to compensate) I should have bought the 6' one. I have to be very precise at the inflation of this one, no air and its the same as sleeping on a blue closed cell, too much air and its like sleeping on a rock! If I get it just right its very comfortable.
The Prolight is ideal for my bivi, it would be even better if it was 6' long. I keep thinking of buying a new Prolite but I just never seem to make the final decision.
When I'm in my tent I prefer the luxury of my Thermarest Neo Air, but this one is not self-inflating. I don't use it when I use my bivi and want to stealth/wild camp, too noisy to blow up. But it is very comfortable and it rolls up to the size of a beer can, which is great when packing my rucksack and am on the move each day.
A long winded explanation (sorry) but the point I want to make is whatever you buy, make sure that your purchase keeps the cold from the ground under your matress where it belongs, if it gets though to your body you can get uncomfortably cold at night.