I recently purchased the Daniel Green Vienna slippers for myself, and since my mother-in-law was wanting a pair of slippers, I ordered this style for her - the Vienna style is a little harder to get on and off. Because of other reviews, I had ordered a size up for myself, and did the same with these. She loves them and agrees that the size is perfect - she usually wears a 9 dress shoe, but I got these in a 10 so she can wear socks with them too. Because they are leather they do stretch a bit over time, but I would still recommend at least 1/2 size up from what you would normally wear. *Note, both pairs I ordered were black, and I'm not sure if other colors are more true to size.
The scuff style is easy for her to get on and off and she tells me that she doesn't have any issues with her heel slipping in them. She wears them all the time and I love that the rubber soles since we have a lot of tile and pergo flooring so there's no worry of slipping when walking on them.
With both styles they look very nice and I wouldn't be embarrassed to go out of the house wearing these.