Been on the same mission of late & imo LAYG devices are not very ideal for these purposes due to the frequent reloads required (that vault one sounds alright though), they also tend to leak if not held upright after a hit to cool down, plus not instant vapour, good for at home though.
Cartridge/tank type devices eliminate all these issues & are just soo much better for out n about stealth, the only downside i can find being the little bit of extra prep/organisation required & having to buy terpenes or similar to make the trates into liquid (only a few drops required so not a big expense & hardly dilutes potency at all, mass-terpenes.com i find great quality & price).
Did find the ccell's a tad hot & harsh & occasionally they clog but not bad by any means, but the next step up from there & pinnacle so far for me is the vaporesso e-juice tanks that have the new euc ceramic coils on a box mod (pico here). The drizzle & the veco ones both work absolutely brilliantly & flawlessly, the veco having more open air flow & the drizzle more mouth-to-lung style, I'm actually fucking blown away by how good they work, took the veco out on the town with some mates the other night & it's just crazy being able to hit the thing in public, it got a hell of a work out, non-stop really, no loading, no learning curve just puff & pass for on-tap porta stealth dabs, like livin in the future or some shit lol. Actually hardly using dry herb vapes at all any more even at home it just seems like too much effort each session, rather just mix up a tank once a week/fortnight & be done with it, no going back here & highly recommended!