King Cole are starting to make some really modern patterns, and this is a great example of that! It looks so good... that knit-on-knit looks like it's made to be. The round neck on that cardigan isn't going to be so wide that it ends up slipping off your shoulders, and even though it's an 'easy to follow' knit, everyone is going to think this is far more complex than it actually is because of that gorgeous yarn. Stocking stitch means that it's a nice, clean garment without distracting from the faux-isle effect of Fjord DK.
This set has been knitted up in Fjord DK, a gorgeous faux-isle yarn, but we'd also recommend using King Cole's Cherish / Cherished / Cherish Dash collection of yarns, which are self patterning and come in a great range of colours. This would work well in pretty much all King Cole DK yarns though.