Trunk comparison: Opel Astra Wagon vs Skoda Superb Wagon

Key Differences
The Škoda Superb Wagon offers a significantly longer cargo floor when all seats are folded down: +18.5 in (28%) compared to the Opel Astra Wagon. Additionally, the depth of the trunk (area between the loading edge and trunk floor) is +2.4 in (300%) greater in the Škoda.
Impact on Usability
The 28% longer loading length with folded seats makes the Škoda clearly more suitable for long items such as slats, furniture parts, long boxes, or skis — such items often only fit or fit more comfortably in the Superb. More loading length also increases flexibility when transporting bulky items.
The greater depth means more usable volume below the loading edge in the Škoda. Since the loading edge height is the same in both models, the effort required to lift items in is unchanged; however, items lie deeper in the Superb, requiring one to reach further when loading/unloading.
Practically, this means more stacking and volume capacity, but somewhat deeper access to the cargo space.
All other differences (e.g., width at the narrowest point +3.1 in / 8% in favor of the Astra, minimal differences in opening width and opening height) are comparatively minor and affect everyday usability much less.
Conclusion
For users who frequently transport long or bulky cargo, the Škoda Superb Wagon is the better choice due to its significantly longer loading length and deeper cargo floor.
Those who primarily value slightly more usable width in tight spots have a small advantage with the Opel Astra, but this is less significant in comparison.