The juice itself is… of moderate known negative impact. The nicotine itself isn’t actually very bad for you. Some of the flavoring though is pretty questionable. Compared to combustion it is likely still quite a bit less negative for your health in most cases.

The exception is the hardware, it seems quite likely there is mass lead and other heavy metal poisoning happening due to poor quality metal and ceramic components in vape hardware. I work in a related industry, and this conversation is being had internally by the big players who are afraid of potential class action lawsuits coming down the pipeline while pure export companies from China and elsewhere sell bulk wholesale of low quality hardware. Vapor composition certifications are coming soon, but the damage may well be done for a generation.