I normally wear a size 8, and had to get a size 9 so my feet didn't hang off the ends.  The soles get slippery against the foot in hot weather, which is dangerous since the heel is free to move from side to side, and frequently slips off the sole, even in dry weather.  The toe thong is uncomfortable compared to much cheaper flip flops I've had.  I expected more, based on all the glowing reviews.  At least they look nice, and and more comfortable than other "dressy" sandals?