I have overpronation and the arch is great.  The sandals are a hard material, but that is ok with me.  It seems when I walk, the top of the sandal flexes to move with my foot-feels great :). I wear 9 1/2 or 10 and so I bought the 10 and it fits perfect!  9 would have been way too small.  I like high arches in my shoes, so this feels great-would like it if there was even more arch :).  I love that I can finally wear flip flops! Worth the money and I am not one to spend a lot...I shop at thrift stores usually to save money and help the community-these were well worth it!