These boots are very comfortable.  I love the low heel, because I don't do well in high heels.  I am extremely picky about comfort, but these boots I can wear walking around all day and my feet don't hurt at all.  I can feel the stiff leather part against my ankles, but it's not so harsh that it rubs or leaves blisters or anything, and it's just because it's new leather.  It will soften up with wearing.  I also love the good treads on the bottom of the boot - most women's boots that look fashionable have crappy soles with little to no treads, which often bothers me, especially in the winter when people tend to wear boots the most.  These are perfect.  I don't have to worry about slipping and falling at all.  I could go hiking in these boots and be just as comfortable and confident walking in them as I am walking around shopping.

I have slightly bigger calves though than the 15" shaft allows apparently, because the boots won't zip all the way to the top when pulled up straight.  However, if I pull them down about 2 inches I can then zip them completely, it just makes the boot have more of a slouchy mid-calf look, which is fine, they still look fantastic.

Sizing - I usually wear an 11 wide, but only because most women's shoes don't come in a 10.5. Size 11 shoes tend to be just a little loose, but 10's are too snug.  I got an 11 wide (c/d) in these and they fit perfectly, so I have to agree with other reviews that you probably just want to order a half size bigger than your normal size.

I spent $100 on these, and I think it's well worth it.  They're super comfortable and good quality so they should last me a long time.  I would absolutely recommend these boots.