I have medium-wide (B width) flat feet, so need a roomy fit. These are fine. The heel slips slightly, but not more than other slip-on boots/shoes so it does not bother me. If you have a slightly wide foot (C width) you will probably also be fine because of the extra room for socks. You will just need to wear lighter weight socks. My calves are on the large side of average and these are roomy enough for my socks and thermals, but still narrow enough that my jeans can fit comfortably over the boots as well.
The style and the quality are very good. The fur and uppers are staying clean and nice looking much longer than I expected considering the mud we trudge through. I like the look of the boots as much as I like wearing them.