The later Quecoo versions (956, 958, 959) seem to have improved internals that address the case grounding, trace covering, tip grounding, and various issues raised about other iterations of T12 stations.
Any proof for that? When looking at AliExpress images - both marketing and buyer ones - I see no grounding wire from the C13 connector to chassis.
I have a 959 (the latest version with an updated display) arriving in January.
As others pointed out, it'd be really neat to hear an update regarding this.
I messaged Quecoo a bunch about the safety and grounding issues that have come up in the past, and can speak specifically on the 955 and 959 since those were the ones I was interested in, though they do reuse the same boards in other units so it likely applies to many other models. Just make sure to check customer pictures/ask the seller, as the display pictures on the site for some models show no iron tip grounding wire on the connector, but recent customer photos show its been upgraded to include one.
So at least for the 955 and 959: the tip is grounded properly and ESD safe for the majority of work, and the board design seems to be good and free from issues like many of the KSGER versions.
BUT: None of the Quecoo chassis are grounded. If you want a safe, grounded chassis on any of their aluminum cased models, you will need to ground the chassis yourself which, while annoying, is a simple task. They do have a plastic/acrylic case model called the Q19 which you could avoid the issue altogether with, but it doesn't have an STM32 as far as I'm aware. They don't have a plastic case STM32 model currently.
I did a large amount of research on these units to ensure the safety for myself and, from what I've gathered, you can get a Quecoo 955 or 959 (or likely others if you prefer) and all you will need to do is ground the chassis to have it ESD safe and safe for the user in the case something comes loose inside. I went for a 955 over the 959 because its compatible with David's firmware, is a more documented unit/style in general, and also just looks nicer imo than the LCD.
I just ordered it so I don't have a personal account of the safety but I did check everything i was concerned about with Quecoo and it should be good to go after I ground the case.