Bought this costume for my 6 year old who typically wears a 6x, I bought the medium after reading reviews describing it as running small and they were correct!  The 8-10 fits more like a 7.  Sleeper is very well made and WARM which is important for Trick-or-Treating in Michigan weather.  The wig is made that well, but it will work for what it's for.  The cap inside is a little too small for her head and there is some glue strings visable but it definetly adds to the costume!  Paint some cute buttons on her eyes and she is one adorable LaLaLoopsy!!!