Even in a DAF the air seat makes a difference, but is a combo of seat and general suspension. I find empty trailers on DAFs are much worse than fully loaded for long runs.
For cars in my experience…
- Vauxhalls are awful for sitting long journeys.
- Kia Ceed isn’t great but better than Vauxhall.
- Fords vary a lot and even though the model.
- Citroen’s are usually quite good.
- Citroen C5 is amazingly comfy.
It could even be the better position in a truck that makes some difference. You get more view (sortof) so aren’t straining to see mirrors etc like in a car.