AliExpress is generally a pretty reliable Amazon-like distribution system.
It's the individual sellers you have to watch closely.
Some storefronts are pretty reputable, like KBDFans. KPRepublic's AliExpress storefront has been pretty reliable to me, but others have had issues. There's lots of specialized keycap stores, as well.
You can get various grades of keycaps from different manufacturers. The GMK clone sets are among the most dubious, however. I have one, and it was a great bargain, and the keycaps are great. But the spacebar was bent. I had to use one from a TADA68 instead.
Those GMK clone sets just aren't built to the highest standard. I'm talking about the no-name PBT ones like G-MKY and such. Some manufacturers are more consistent and higher-end. AKKO makes clones of some GMK keycap sets, and their keycaps are said to be straight. But their legends are ... not great.
ePBT has a line of ABS keycaps, but they are bad. R3 interference. So don't buy them. The actual EnjoyPBT PBT sets are often quite good, though. Check-in the GB pages to find out how their molds are doing before getting in on a group buy.
Domikey got into Cherry-profile ABS [or maybe it was PBT or both] recently. They made okay-ish SA clones, and should probably be able to handle Cherry-profile sets 'inspired' by GMK. [Some of their sets are original.] I would take a serious look at Domikey. Also, Akko [but bad legends].
They just had a big winter sale, could get at least 10% off on keycaps. Don't know when the next one is.
