I find the Land Rover is more comfortable than my every day driver for long journeys.
My "family" car is an Audi A6 and after driving long journeys (over 100 miles) I suffer chronic pain in the posterior sacro iliac area (RH) despite trying many seat configurations, including altering the lumbar support. If I repeat the journey too soon after, the pain can take 2-3 days to subside.
However I can spend all day behind the wheel of my Land Rover (04) without similar problems. The only time driving the Land Rover caused me similar problems was before I fitted the longer seat rails, when I would get minor twinges in the anterior area.
The only discomfort I now suffer in the Land Rover is now down to the "handbrake left leg abrasion"; the "trench foot" in the right foot due to leaks, and a "numb bum" due to lack of padding (in the seat, not my posterior).
My layman's view is that the difficulties with the Land River arose because of the lack of thigh support (not brilliant in a LR) particularly with the shorter rails meaning that my right thigh was always above the seat squab when driving, particularly if on motorways/open roads. The extra couple of inches made life so much more comfortable (No smutty comments please).
Similarly, as I continue to suffer with the Audi, I have concluded that some of it could be attributed to the fact that it's an automatic, and therefore on long motorway journeys my right leg remains relatively static for longer periods. However, I have tried, using cruise control, to exercise my leg/hip joint whilst on such long journeys without much success in alleviating the onset of the problem. So some of it, I assume, is down to seat design/ pedal layout influencing my posture whilst driving.