If VariTube.com didn't offer the Sigelei Zmax starter kit for $89.95, I'd go with the Vamo, but I just can't pass up that price on a machined stainless steel VV/VW APV. They're out of the kit at the moment and just offer the body for $79.95, but they're supposed to have their stock replenished next week. The kit comes with a case, charger, 18650 and 18350 batteries, both end caps, and a clearo.
@Uma...VariTube told me that the 510 connection depth "issue" is really a non-issue except on the voltage meter that Phil Busardo tried unsuccessfully to use at a little past 8 minutes into the following video. They said that the only connection problems are with defective cartos/atties/tanks with recessed center pins as opposed to flush or protruding center pins...in other words, the lack of contact would be due to faulty accessories and not the Zmax itself. They also said that any device that couldn't make contact could be made to work by using a standard 510-510 adapter. For the price, I can go with that.
I'll still probably get a Vamo for on the go, though. The price is right and it appears to be using the same circuitry as the Zmax V2, just housed in a stamped metal body...not that there's anything wrong with that.