For checked luggage, I prefer the hard shell ones since once they’re out of sight, suitcases go through a lot. Plus airport ground crews aren’t exactly known for being gentle.
Brandwise my family had at least one VIP suitcase that lasted for 30 years at least. Finally gave up the ghost just 5 or so years ago. They’re quite sturdy and reliable. Safari is another brand I like and have been using for the past few years with no trouble. And with the recent-ish rebrand, they have some pretty cool designs as well.
Honestly though I don’t think materials wise there’s much difference between most of the reputable brands at least. Just the guarantee/warranty terms and how likely the brands are to honour them.
No-name brands I would not trust the quality. And the more expensive ‘lifestyle’ brands are just whitelabelled goods, which also I would avoid. Or at the very least just buy directly from the Chinese seller on Aliexpress or its current equivalent, for prolly a third of the price.
For carrry-on luggage I have my trusty Nike bagpack that I got as a gift 20-odd years ago now. It’s been through a lot and looks it. Now that I think about it, it prolly needs to be replaced. And if I were to buy something now, I would prolly go for some sort of large-capacity (but not the giant trekking packs), waterproof bagpack rather than a suitcase or other kind of bag, since it keeps the hands free. Plus, having it on my back means less chance of forgetting it somewhere or worse, getting robbed. Waterproof or at least resistant because stuff happens. And I don’t mean rain cover but that the outer material itself shouldn’t get wet easily. If it has a rain cover with built in storage for the cover, all the better.
For bagpacks I don’t think I would really look at brands since, again most of them are prolly made in different floors of the same sweatshop factory in Bangladesh or wherever.
As always when ordering online, check the return policy before paying for it, so you don’t get stuck with a something unsuitable.
For suitcases check that it’s light-weight, so it adds as less as possible to your checked in weight. Also check the wheel roll on as many different surfaces as you can and the handle extension and how easy that mechanism is to extend and retract.
Bags, put some weight in it and see how it feels on your back; straps should be padded and not bite into your shoulders; it shouldn’t flop or bounce around on your back when you’re walking with it; the weight distribution should seem more or less even across the back. Most of this might just need adjustment of the straps, though in rare cases its the bag construction.