Having sat and looked at both, I would agree that the materials in MkIV are significantly better.
About a week ago, I sat in few cars (Pilot, Fit, Tiguan, Rabbit, Mazda3 - mine, Astra and Outlander -mine) within a few hours interval. Out of all small cars, speaking strictly about the interior materials quality, I think the Astra is the best.
It's the only one that has soft-touch materials on the dash and door panels. The Rabbit is all hard-plastic even though it feels of relatively good quality. In my books now the Rabbit is at par with the Mazda3 in terms of interior material quality and maybe a notch above the Civic.