For check-in
luggage, the advantage with a hard case is that it is more difficult to crush the contents, so if you have fragile items inside, they are less likely to be broken by an impact. The weak point, however is the zip, and on cheaper cases, you will find that they tear easily and the contents of the case will fall out, while the shell of the case is likely to be okay.
The downside is that the case is going to get scratched, because luggage handlers do throw them around. However, some frequent travellers like to take pride in this to demonstrate that they can afford lots of air travel!
Soft-sided luggage is less likely to show scratches, but there is a tendency for the seams to fall apart when crushed. Zips tend to be fine as the seams are weaker. Sometimes these tears can be repaired . Repairs are obviously more challenging if you have a hard case.
For cabin luggage, all the above is less relevant as, in theory, you should be looking after your own bag. You may decide that a soft sided case is easier to fit in an overhead locker, particularly on smaller planes as it can be compressed slightly to fit. A hard case would be more difficult to fit in an overhead locker on a small plane, and there is a risk you`ll scratch it on latches. Soft cases will also usually also have outside pockets which make it easy to store things you might want to access quickly on the plane.
Ultimately, the investment decision is down to how comfortable you are with your belongings being thrown around.
Zhejiang Yinglin Luggage Co. Ltd