I ordered a pair for each kid and they arrived yesterday and I LOVE THEM. I wish I had these last winter too. They stay on better than socks and are fully adjustable. And they're gosh darn cuuuuuute. The babies look like they have Grinch feet. I was worried about them slip-sliding from the fleece on wood floors, but they haven't had any issues at all.
Both babies slept with them on last night (they wear two piece, footless PJ's) and when I got them this morning their booties were still on! I love these little booties so much I had to share.