If they can't even get the product to match the picture on the box, what makes you think they can weld to a spec? Or they care what grade steel they use? I think this is the wrong thing to try to save money on.
Edit: As I look at it, the weak link is the bogus casting, not the weldment. Lord knows what the Chinese put into those castings. They put sawdust in baby formula that killed babies.
The other designs that use pipe and a cross pin, at least you could tell if the pin was damaged, bending, or the hole in the pipe was elongating.
THAT SAID:
I have a set that looks like these that I bought from Sears 30 years ago. They are made from welded extruded angle, but have a similar cast saddle. Don't know why I've felt safe under those all these years. They have never let me down. I'm sure they too were made in China. My guess is they these things never fail. I guess I just don't want to be the one in a million. Especially since I have the extra $100 to buy US made stands.
How about this- if you buy a set of these, at least do a proof load test before you get under a car supported by these. Check every tooth. Load them as much as you can then inspect for cracks after each test.