I found my first pair of Sanuk Yoga Mats by accident while shopping a local surf shop.  I fell in love as soon as I put them on.  I am very picky about my flip-flops they must fit well and must be comfy. These are great! Very soft and squishy, but not so soft that they're hard to walk in. Also, the piece between the toe is a soft cloth so no blisters...and I didn't have any break-in period.  I'm on my second pair because I love these so much!  I normally wear an 8 or 8.5 depending on the shoe.  The 8 fits me perfectly.

SHOE SIZE: Felt true to size
SHOE ARCH: Moderate arch support
SHOE WIDTH: Felt true to width