I have used Robeez with all three of my girls.  These run bigger than the standard Robeez.  I am thinking it is because of the sandal-type design.  I bought a size 6-12 month for my 13 month old and they can still fall off somewhat easily.  I am hoping she will grow into them this summer.  They are super-cute and the light pink color is almost a neutral so I know it will compliment many outfits.