I buy a lot of industrial components on Alibaba. Only issue I've ever had was some stepper motors that were miscolored on the wiring. Took me a lot of diagnostics to figure it out. Killer was that not only were they not correctly colored to the wiring schematics, they were also not consistent among the set. Stepper motors are dead simple to wire once you figure out what the problem is. But it was a big PITA to diagnose what was going on.
For stuff like linear motion equipment, small batch electronic components and PCBs, and the like - it's my go-to marketplace. There's often no where else you can even get some of those things. I've never had a product show up that wasn't as described by the seller other than the set of steppers.
About half the "overland" stuff you see is available on Alibaba - including things like almost every overland trailer that's marked up 4-5 times the price you can buy directly from the mfg in China. And you can spec it out exactly how you want it. My wife didn't like the Black series trailers or I'd have ordered one directly from the same factory that builds them. Difference is that it's $15k to the port in Cali instead of $50-60k at a local dealer.