Trunk comparison: Mercedes Benz CLA Shooting Brake vs Skoda Superb Wagon

Key Differences
When all seats are folded down, the trunk of the Škoda Superb is 13.8 in or 20% longer than that of the Mercedes-Benz CLA. The trunk opening of the Škoda is 4.3 in or 15% higher and its opening width is 7.5 in or 22% larger than the Mercedes.
The Mercedes, on the other hand, has a significantly deeper trunk well (depth from loading edge to floor): +5.5 in or 175% compared to the Škoda, and the loading edge stands 6.3 in or 27% higher above the road.
The narrowest width in the trunk differs only slightly (Mercedes +1.6 in / 4%). With the front seats upright, the lengths of both trunks are the same.
Impact on Usability
The Škoda Superb clearly has the advantage when transporting long and bulky items: the greater length capacity with folded seats plus the higher and wider opening make loading, maneuvering, and storing long, wide, or bulky items easier. Additionally, the lower loading edge makes lifting heavy loads simpler.
The Mercedes-Benz CLA offers a significantly deeper trunk well, allowing cargo to sit lower.
This can help position bulky items lower or store luggage under a cover, but it does not offset the disadvantages of the smaller opening and higher loading edge: heavy or wide parts are harder to lift and more difficult to maneuver through the narrower, lower opening.
For everyday use (shopping, luggage with front seats upright), the models are similar since the trunk length does not differ then.
The deciding factor is the usage profile: frequent long/wide or heavy/bulky loads → Škoda Superb; occasional use with an advantage for a deeper loading floor and slightly larger narrow width → Mercedes-Benz CLA.