Do you want the accurate answer or the useful one?
Think like a data miner and you'd see fertile ground for theses and dissertations. You'd look forward to years of grant-funded number-crunching, with an endless list of factors and responses to study: brand/flavor/additives of juice, delivery system, environment, age, income, education, parallel substance consumption, medical history, location, social status, ethnicity, gender identification, etc. You'd withhold comment until your own study is published.
Think like a gambler instead of a researcher and you'd bet that the results of any given study will look something like this: vaping has been shown to be associated with X% increase in the risk of disease Y. Just like all other research studies on all other topics do.
Think like an activist and you'd disparage both vaping and smoking, except for legalizing marijuana.
Think like a chemist and you'd describe how Juul inhalants are the generally predictable gas phase of mostly innocuous juice ingredients rather than a highly variable mixture of combusted and semi-combusted carcinogens.
Think like a vape manufacturer and you'd plan for evolution in the ingredients of your juices. Each new version would be marketed as an increase in pleasure and/or reduction in health risk.
Think like an economist and you'd point out an unintended consequence of tobacco taxes. As smoke from the lit end is pre-filtered by the tobacco at the rear, it will leave creosote-like deposits on the unburned leaves. When cigarettes were inexpensive, smokers might light one but go through only half before discarding the more tar-infested remainder. As taxes increased tobacco's price, I now observe the same smokers burning each one down to the filter to extract the maximum value - as well as the maximum tar/nicotine/ash/monoxide/poison - from their increasingly costly resource. Vaping does not present this mechanism.
Think like a vaper and you'd argue that you typically take only one or two hits per occurrence, not the two dozen draws it takes to consume a full cigarette. So even if the vape juice is as full of nasty stuff as are tobacco fumes, a vaper will inhale fewer toxins.
Finally, think like an ordinary schlemiel (i.e., me) whose only data is anecdotal observations of people who have successfully used vaping as a means to wean off cigarettes. You might regard it as the lesser of two evils.
