I would much sooner use a single-beam name-brand contact than triple or quadruple beam aliexpress contacts.
In the end, the answer really depends on your needs. You can get clones of Molex SL (which is similar to C-Grid III), but I doubt they’re as good.
What’s the application exactly? If you just need one or two insertion cycles, cheap stuff is OK. But if you need more cycles, then you really don’t wanna cheap out. Cheap clone DuPont contacts are brass, which loses springiness very quickly, especially in the Chinese DuPont design. They get dramatically looser after just a few insertions. In contrast, Amphenol Mini-PV are good for a thousand cycles — they cost 20x as much, but last 200 times longer.
Some of the cheapest name-brand connectors are JST. Their own online store has surprisingly cheap shipping from Japan. For the most common JST contacts, reichelt.com (Germany) sells the original tooling at extremely competitive prices, even with shipping.
But I think the first thing you should decide is what your priority is. You start off by wanting a cheaper alternative to an already cheap connector, but then say it’s for non-hobby laboratory use, where I would think high reliability is far more important than saving a few cents. (At the university where I work, the mentality is absolutely one of dependability over cost, since you don’t want a failed 20¢ connector wasting hundreds or thousands of dollars in labor, or worse, even more if an entire experiment is ruined.)*
As for whether the gold really is or not: I don’t have the knowledge and materials to test it, but I haven’t had any problem with supposedly gold plated Chinese DuPont contacts. I have, however, had problems with some “gold” PCB headers! Whatever they were, it wasn’t gold, because you couldn’t solder them. Even with extra flux, they just wouldn’t wet.
* I once had to cut off and replace 50 contacts, at $3 each, because they had given me incorrect specifications the first time around…