Works very well, especially for the price. No one has much in the way of reliability data though, as it is too new - but at that price you could almost say if it works for 6 months you're well ahead of the game. Plus it has some good features: voltage readout, voltage lock, digital master on/off switch. It's very light and compact for what it is. That means it has a slightly less than substantial feel to it - but the benefit is light weight.
You may be better off substituting an AW cell for the included one because the OEM cell has no reliable data on cell type or manufacturer. Flat tops or nipple tops will work, so an AW 18650 of any type will work. Doesn't have to be a flat top like the OEM cell.
Someone lent me one for a few days and I was impressed - it's what a VV
mod should be and better than the price says it is.