Regarding the Pilottenkoffer, hand-carry model, it is a good case, but when and if I use mine now it is as checked luggage. I find them entirely practical, but heavy.

As I mentioned previously in another post, running to catch a flight one evening in Milano Malpensa using this case was an experience. The case was banging around my kneecaps as I did not take the shoulder strap along. Big mistake. I elected to use something else after that experience.

The 2 and 4 rollern models of this case make much better sense, the design using the better features of the older alu Bordkoffer and a rolling wheel carry-on. I have no experience with this newer model.