I'd say that it depends on what you are looking for. Both jeans fit well, the RB15 considerably slimmer than the Svens, and with a slight taper compared to the true Sven straightleg. If you are looking for a beat around jean that has a good fit and will give you a good fade, go with the Sven. If you are looking for a more versatile jean (Nudies, with their orange stitching and back pocket design, are, imo, strictly casual) and want to keep the darker cast for a longer time, go for the RB15. I would say that the RB6 is actually more versatile than the RB15. Best thing is just to go to a store and try them on. Where are you located? Both brands have pretty wide distribution.