I have had a pair of these shoes in black leather for three years and love them. Breaking them in was a non-issue. I put them on and they were instantly comfortable, cute, and they went with a lots of things in my wardrobe. I could wear them in virtually any kind of weather except for a snow storm and they serve me well.
My other pair in this style is taupe suede. Took no time for break in, but the suede seems to have a bit more 'give' the longer you wear them. My only suggestion is to buy this in the appropriate width to get a good fit. I wear between a 9 1/2 to a 10 with a normal width. This translates to a size 40 in Birks and a regular width.
I own a lot of Birks and I love them all. They are really comfortable shoes and I rarely buy any other brand with the exception of Arcopedico which are really comfortable too.