I used to have the nf de and sold it and used the money to buy my cabas rivington. I love the cabas..its not as common as the nf and it has the look of the nf and a bucket tote( when zipped). I also think that the cabas straps will age better and are less prone to cracking due the the hardware on the straps. The hardware allows the straps to fall in any position and not bend the straps excessively.
The cabas straps did hurt my shoulder in the begining because the leather was so stiff...but now that i have used it for a few months the straps have soften up. It is double the price of a nf but well worth IMO.
I really like the look of the Cabas Rivington bc to me, it looks like a unique twist on the NF. But while you say, assuming both bags have the same price tag, are you and your friend aware that the Cabas Rivington is about twice the price of the NF? At that big of a price difference and a similar look, I would go with NF or a bag that looks altogether different for the Cabas price.
Yes I am aware of the huge price difference between the two bags and have mentioned this fact to my friend but the uniqueness of the Cabas Rivington is one of the reasons why she's considering it.