These just came in the mail today.  They were so cute, and I didn't have trouble slipping my feet into them at all.  Unfortunately, the shaft is too small for my (giant) muscular calves.  Although it says that the shaft opening is about 16 inches, that's probably the diameter at the very top, just below the knee.  These boots are definitely not 16 inches around where my calves are widest.  I was able to zip up the left one with some difficulty.  Couldn't zip up the right one at all, and I was only wearing tights!  Anyway, my right calf is about 15.25 inches at its widest part; the left one is about 15 inches, in case you were wondering.

I'm still giving them four stars though--it's not the boots' fault that my calves are oversized.  They are otherwise super cute and comfy.  I'm really sad that they don't fit.