Nobody yet. The 3-amp versions (Young June v1.5t) now available were incorrectly advertised as having a 4-amp limit. They don't.
Supposedly, the Young June v2.0 now shipping from China in chrome-covered brass will have a 4.0 amp limit, but that is yet to be verified, since the vendors who ordered them are waiting for delivery, which should be any day now.
CrystalClearVaping will be among the very first vendors to have those v2.0 chrome units. CCV is offering them as replacement exchanges (with a small upgrade fee) for customers who bought a v1.5 from CCV, which turned out to have a potentially dangerous defect where one of the
three chips might short and cause a serious meltdown. (Young June has reported that this defect was subsequently fixed, and that all current v1.5 and v1.5t units being sold are fine.)
Soon, Matt. Soon.