I smoked Nat Sherman's, which are additive free. They also use much higher quality tobacco, and use only the center part of the leaf with no large veins or stems (which are filler products in even the best drug-store brands of cigarettes). They are a much different experience than even the highest quality drug-store brand cigarettes, including American Spirit. For a single cigarette, the smoke of a Nat Sherman much denser and less harsh. The Sherman will also burn a lot more slowly, so you either become a more aggressive smoker or take longer smoke breaks.
Over time, smoking habits tend to become pretty different for Sherman smokers, too. When I couldn't get to a tobacconist to purchase Nat Sherman's, I'd buy Marlboro Reds. Although they were much harsher, I'd quickly find myself smoking more than a pack and a half a day, even though with Nat Shermans, I'd usually smoke a little less than half a pack per day, 8 or 9 cigarettes. On a day that I stayed up really late, I might smoke a bit more than a half a pack, like 13 or 14 cigarettes.
That's just my personal experience, though I've spoken to others who have related the same. Also, I've spoken with tobacconists who have told me that many of their cigar smokers quit smoking cigarettes altogether after changing from drug-store cigarettes to Nat Sherman's. Nevertheless, this is 100% anecdotal, so don't go out and buy Nat Sherman's thinking that they'll make it easier for you to quit smoking.
Now to the original question: There's no comparison between vaping and smoking Nat Sherman's. If you smoke cigarettes than you're inhaling smoke -- even if it contained zero harmful chemicals, you're still filling your lungs with ash at a faster rate than your lungs are able to recover. And, unfortunately, no matter how good and pure the tobacco, if you're burning it then you're breathing in a host of toxic chemicals created by the combustion itself.
Sherman's (or other additive-free tobacco, if they're interchangeable) may be marginally safer than drug-store tobacco brands, but they also might not be (they could even be worse; there's been very little research on this), and there's no comparison at all with vaping -- not even measurable on the same scale.