The "vivid vanilla" used in Blu cigalikes is really pretty good but you can't buy it except in blu e-cig cartridges which are -ridiculously- expensive. Johnson Creek Vapor company makes the Blu "Vivid Vanilla" juice but the vanilla flavored juice they sell from their own site tastes -nothing- like it. I've tried scores of ready-made juice that touted "Vanilla" in their name and while many people will claim this juice or that juice "tastes just like vanilla" or "It's the best vanilla I ever tasted" I've personally not found a single one I'd buy again. Taste is highly subjective but most of the ready made juice I've tried required significant "imagination" in order to discern any vanilla flavor at all.
I've also bought/sampled every single concentrated vanilla flavoring on the market. For me the best are "Holy vanilla" and "French vanilla" from DIYflavorshack and "Vanilla" from Lotus. Lotus vanilla is a true straight vanilla flavor although a bit subtle, it's mixed no higher than around 1% and I blend it with Holy vanilla. Holy vanilla is also a true straight vanilla flavor and is mixed at 7-15%. French vanilla tastes like French vanilla ice cream and is mixed between 7-15%. Two other concentrates I used to recommend have recently re-formulated their vanilla flavorings and no longer tastes anything like vanilla. Same problem with most concentrated vanilla flavorings on the market, they don't taste like vanilla, not even close. Pudding, cookies, wax candy or floral deodorizing room spray perhaps but not vanilla.
I extract tobacco and mix NETs. I enjoy hybrid (flavored) NETs and vanilla is my favorite secondary flavoring. For my Vanilla Tobacco I make a concentrated vanilla flavoring using 0.75% Lotus vanilla, 5% Holy vanilla and 7% natural bourbon (Madagascar) vanilla bean extract that I make myself. The extract provides a sweet earthy, woodsy vanilla undertone while the concentrated vanilla flavorings add the higher notes the extract lacks.