I have these in brown.  They are SO comfortable.  I have tarsal tunnel syndrome and have had surgery that only half worked, and these shoes, amazingly, do NOT irritate the nerve in my foot.  My friend has some, and she said she had balance problems at first, but strangely, although my balance is awful, I actually feel MORE stable in these shoes.  I'm not sure why that is, but I sure am glad.  To me they feel more like walking barefoot than a lot of shoes, and that is how I walk best.
I could tell after the first day that they seemed to be exercising my lower calves a bit, and my husband commented that I was standing up taller.  My friend says she can't tell a difference in her posture, but I have noticed - they obviously have helped mine.
The shoes look very nice on.  The strap is velcro and it stays on very well.  I also have been wearing these out in my garden a bit, without thinking, and they've been easy to keep clean.  I got dirt and water on them the other day, but it brushed off and I can't even tell. Whew.  They were high and I was scared I'd ruined them, but nope, they cleaned up great.
My ONLY complaint is that they are a bit hot.  I've been using foot spray to keep them from getting stinky, because the ARE rather hot to me and I don't think they'd look right with socks.
I personally find them more comfortable than Crocs.