I wear an 8 and ordered an 8 and the fit was perfect.  I do not have a (b) narrow foot but I would say that my feet run on the narrow side.  If your foot tends to run wide I would think these would not work well for you.
I wore them the first time shopping and they did not bother my feet or back at all.  I was concerned because I never go over a 3" heel but these worked out very well and I had several women and even one man comment on them and ask where I got them.
They do have a cardboard insert that at first I did not realize was in them and I thought ouch...these are horrible...haha  then I removed it and it was like slipping a fur lined glove on my feet.
I like them so much I got the iron color first and then went back and ordered the brown.
I do have a small complaint as the first day I wore them one of the thin straps broke.  I was able to repair it..the shoe is made however that if you had to remove the straps they would still be adorable.
Super happy with purchase price, fit, comfort, quality, color and the super cute factor.