When they say the underwire will not dig in, they mean it! They is probably a good 1/4 inch worth of padding on the underwire!
The straps really do fit perfectly. I was skeptical too, even when I saw it. They didn't even seem stretchy, and I like my straps very long. They really do not dig in or are so big that they slip down the shoulders. Also, it is almost completely seamless. Other than where the straps have to connect to the bra it is totally seamless on the outside, and I think the inside, but I would have to take it off to check and it is so comfy I don't want to!
Seriously, I know they are a little more expensive than most of the bras there but so worth it! I am going to the store to get another demi as soon as I can!