After wearing the flip-flop version of this sandal, I decided to order the Sierra. This is the sandal you can wear for a 5 mile city walk right out of the box without a breaking in period. I love the extra support the strap and heel protector offers. The strap hugs your foot to the shoe so you don't get that slap to the bottom of your heel that you feel with flip-flops. The piece between the toe is super comfortable too. The only negative is that they are a little awkward to buckle so probably wouldn't wear these on a day you need to slip your shoes on and off a lot. Shoes run true to size.