This is a purely subjective assessment of each. One of the advantages of the train is that you can get out of your seat and walk around... which you can do on the Volvo of course, but subject to the roll of the buses. Another is that you can use a toilet instead of having to ask the Bus Driver to stop somewhere...
Another is that you get food on board when you want, not when the driver wants !
The leg space availability is simply a matter of subjective assessment of each...
more... passenger ! repeated again deliberately.
good wishes.
PS: Although I am a rail fan, I too travel long distance by buses and my own car !