I am a big fan of MBT's.  Shoes and style are very important to me, but I chose to invest in them after suffering from the limited mobility of plantar fasciitis.  They are expensive but worth every penny as far as I am concerned.  I live where I must walk all the time.  I believe they do every thing as advertised - they absolutely help firm my leg muscles.  The construction puts them leaps and bounds ahead of the Sketcher Shape Ups.  I won't go into great detail because that is not the point I am trying to make with this review.  I have been confused with sizing.  I normally wear a 6.5 M in the US.  I live in Germany and know that shoe sizes here can vary by company - more so than in the US.  Most styles offer a 36 1/3 size which is advertised as a 6-6.5 and fits me perfectly.  However, some of their shoes aren't in the same sizing pattern, such as this pair.  But these were the closest to 'feminine' I could fine to go with summer clothes and I needed to take a chance.  They offer a 37 which they say is also 6-6.5.  I have 37 boots which feel a touch big however I can wear socks to compensate.  Sandals, however, must fit perfectly especially without a back strap.  I was afraid to order a 36 especially when it is described as a 5-5.5.  These just showed up and they are not quite right.  The foot bed seems perfect so I am happy with the 37 from that point of view.  But the straps are a little loose.  I will keep them and not return - I put in a Dr Scholl's gel insole which gives it just enough tightness so I don't have the sense that the shoe will fly off.  But I am a little disappointed that the adjustable straps won't go any tighter.  That said, from the side they are *almost* cute so I will wear them with sundresses!  :)