Oh, my experiences are dramatically opposite and yes I read reviews anywhere I can and also write them. I would say that more than 50% of first time purchases are unusable and I am so to say resigned to that. Those that are usable are on the OK side. Maybe we differ in standards

. Also I talk about the first-time purchases because, when something actually works, I may buy it again. I also wonder, in the context of your claimed experiences, why mainland Chinese are sometimes ready to buy a foreign-branded product at a cost few times higher than nearly identically looking domestic product. Do they have access to some mysterious knowledge that, under commonplace circumstances, they just look at a domestic vs foreign label???
If, unlike mine, your standards are so high, why order anything from Aliexpress in the first place? You could have ordered bag for your chain from Brooks or some other well known, none Chinese brand. No?
I've ordered SON Edelux II which is supplied with fork bracket suitable for Brompton. I actually didn't know the bracket will be supplied in the box so during the process of placing the order I've ordered stand alone SON fork bracket suitable for Brompton. So now I have 2. It places light so high up that its too close to the bag when mounted on the front carrier block making light unusable for me making me go and order alternative bracket. German company, product bought off a German website, produced in Germany, shipped from Germany.
And the Brompton specific TRIGO fork mount I previously ordered from Aliexpress for battery powered headlight worked like a charm. From China, made in China.
So yeah, experiences differ.
I've ordered $65 titanium seatpost from Aliexpress which was listed as 600mm which is exactly the length of my stock seatpost. The one I received was perfect, except it was 580mm. I've made few pictures showing the length difference and sent them to the seller. They apologized and immediately sent another one, asking me to keep or sell the 580mm seatpost I received. Your experience can definitely be different, just as your experience with any retailer in the world.
Would I buy a Rolex watch from China over the internet? Probably not. A bag for bicycle? Will definitely give it a try.