Depends on who they are and why they are travelling. Case in point....
- most of my colleagues use wheeled cases as we travel 90% of our work and our laptop cases are our 'office'
- I DON'T use a wheeled case as I do a lot of international travel, where carry on rules are stricted. I have a German laptop case which can expand enough to allow me to carry some clothes as well as my 'office' but is still small enough to fit European rules
- sometimes if going on vacation I don't use a laptop case - I use a neoprene sleeve to protect my laptop and put it inside a messenger bag
- others use a standard 21 inch carryon and put the laptop inside, in a sleeve, to protect it (my grandparents do this when the travel - yes, at over age 90 they bring theirs along)
I like my case best as I can't carry things on my shoulder for more than a few minutes, and the case fits on top of a roller suitcase. Otherwise I carry it by the handles (which are longer than most I found in the US)
It took me about a year to find the 'right' case when I went shopping for one last; but I had some very specific requirements due to the amount and type of travel.