To me, the Roulis is one of the most versatile bags and can easily go with casual or dressed up looks. The leather strap is not overly thick and doesn't draw any attention (at least to my eyes). I am regularly wearing mine out for dinner (the bigger size, though) and have several people compliment me on that wonderful bag. Due to the fact that it is so streamlined, it can easily transition from day to night. I cannot comment on the Mosaique as it gives off a completely different vibe and aesthetics. To me, the latter would be a weekend/casual bag as I feel it has some very distinct features and therefore is less easy to combine with varying looks (although it is a wonderfully constructed and cool bag).