Just arrived. Seems comfy & sturdy after just a few minutes of walking. Sturdy with flip flops is an import ant feature for me.
Im thinking/hoping there will be little "breaki-in" needed as thong between toes is good.
Will update after I do some serious walking with them.

Also, I am size 9.5. Womens size 40 i(USA 8.5 -9.0) is just right--with ample room in front of my big toe. I could not walk in anything bigger.