I bought the white pair with the purple elastic.  I wear an 8 1/2 wide shoe and I bought the size 8.  They were a little tight so I stuck them in the dryer for 3 minutes and put them back on with a pair of thick socks and wore them around a bit (they fit perfectly now).  When I first got them I couldn't believe how comfortable they were.  I wear them to work (I'm a teacher), walk the dogs, do yard work, to go shopping, etc.  I wish they were the only shoe I would ever need to wear.  I work part time as a server in a restaurant and I have to wear other shoes, but as soon as I get home I have these on.  I loved them so much I bought my mother a pair (size 10, she has very narrow feet).  She loves hers as well.  I recently became a crocvert, and own four pairs total, with my fifth coming tomorrow (from Amazon).  The springi's are my all time favorite shoe.  My feet don't sweat and they don't make any noise at all when I wear them barefoot.  I had nearly constant metatarsal pain in my left foot (5th meta) and I don't with these shoes.  They are flippin cute too!  Buy them, you will love them this summer!

**Update** 7/07/12 - Having worn these shoes almost exclusively since I bought them and having bought them for both my mother and my niece, there is one complaint.  The back begins to rub very agressively on your back ankle.  It doesn't happen right away, but when it does its more than a blister, it will bruise the area.  I stopped wearing them for about a month and recently put them on.  I think if you wear them for short periods of time you'll be fine?  All three of us had the same issue independently of each other (the bruising of the back ankle).  Maybe the elastic is too tight?