Had mine for about a month now, and I have to say it is excellent. Mine is slightly customized (smaller hood) although I actually think the default size is a smarter option than what I thought up. Mine uses M50, in wide, and weighs in at about 5.4oz on my scale.
I'd never used anything with momentum before, I was more than pleasantly surprised with its water "resistant" qualities. As in, I didn't know you could line a bowl with it and fill it with water and not get the bowl wet. I really don't know how long you have to have this stuff submerged for it to give, but with a well positioned tarp it is pretty amazing. Maybe that diminishes in time or something, I don't know.
I have used a large 25' wide neo-air, and it was still extremely roomy, even though I am a skinny wuss, I am somewhat long and I had an enormous amount of space. Breath-ability is good. I did have a tiny amount of condensation in the morning, but I also live in a coastal rain forest, and this has handled that fact better than anything else I have used in such proximity to my body.
I wouldn't hesitate recommending this to anyone. Considering the weight and price, I have yet to see a better deal short of trying to sew your own.