My toddler is a tall & slender 21-month-old, and the 24 month size fits her just fine with (I hope) enough growing room to last the winter... we'll see. The fleece is very soft; it isn't the thickest ever, but still seems reasonably warm. I took one star off the review because I had been hoping for a thicker fleece, and when it gets really cold at night, she ends up needing a blanket also.
I ordered the "Zebra" because it was on sale (less popular design?) figuring that even if it's an unattractive print, she would be wearing it in the dark while asleep, so it really wouldn't matter. Turns out the pattern is actually rather nice, the colors understated and easy on the eye. All in all, I'm very happy with the product and would recommend it.