People who vape and use Snus are in that percentage of ex-smokers who are dependent on the other active tobacco alkaloids such as nornicotine, anatabine, anabasine and myosmine, as well as nicotine. In theory WTA liquid can provide these although no full analysis of these refills has been published, so we don't really know. We do know that Snus fixes it for virtually all of those who still experience cravings even with a high-strength of nicotine in their ecig refill. Those whose issues are not resolved are presumed to be dependent on other compounds in tobacco smoke.
Note that the highest retail strength of e-cigarette refill liquid is now 45mg (4.5%), it was found necessary to raise it as low-performance equipment such as mini ecigs don't provide enough nicotine to the end-user. It is less of an issue with a mid-size ecig or an APV. Before you can conclusively say that ecigs are not fully effective for you, you must try the higher nicotine strengths. In general a balance has to be struck between reducing cravings and over-consumption - you can go as high as you like, until symptoms of over-consumption start to appear - then back off. Generally speaking it seems that those who are more tolerant to nicotine, need more, in order to fix the cravings issue. There is a difference of a factor of 10 in the individual's tolerance for nicotine, so people vary very widely indeed.
Swedish Snus is different from that produced in other countries because it is carefully processed ('steam treated' or 'pasteurised') to remove most of the carcinogens, and complies with an industry voluntary standard that dictates the maximum level of such ingredients*. This may or may not apply to products made elsewhere. Genuine Snus must be kept in a fridge.
* The Gothiatek Standard:
GOTHIATEK® standard - Swedish Match
Snus is not combined with ecig refill liquid in any way, it is used separately. Specifically, if you are experiencing cravings that en ecig cannot satisfy, then use a portion of Snus. It generally comes in a tiny flat packet that is placed behind the upper lip: at the front of the mouth, between the upper gum and upper lip. Leave it in for as long as is needed; the average time seems about 45 minutes. Please dispose of the used packet in a bin, not on the ground.
One issue needs to be noted: some Snus products contain substantial amounts of nicotine, and combining vaping (especially with a high-strength refill) and Snusing may take you over your personal limit for nicotine tolerance. You will soon know if this happens as various unusual effects are apparent. Stop one or the other and these effects soon go, they are neither long-lasting nor serious (it's the same as drinking too much coffee).
There is a considerable amount of material comparing Snus to ecig use in one way or another on the ECCA UK site (the UK ecig consumer association). Mainly, this is about the politics, but there is some other material such as how Sweden is the world leader by a very long way in the reduction of smoking-related disease and death. The site search brings up some but not all of the material:
ECCA UK - E-Cigarette Consumer Association of the UK
