I ordered these for my 4 month old son. The booties are great! Warm enough for colder weather but light enough for spring/fall. They seem to run small. My baby is just 4 months and I ordered the 12 month size. He has room to grow a bit but they stay on his feet just fine. We wouldn't have made it to spring had we ordered the 6 month size.

The elastic at the back of the booties is wide so I don't anticipate issues with it leaving marks. The snaps hold tight and the ankle area provides good coverage when baby's pant legs scrunch up. I could definitely see myself ordering other colors.