The OG VV is neat, effective, simple to use.  As soon as the batteries were charged I tossed in a filled bottle, put on a fresh atty, primed it and vaped.  The voltage control is an easy to use white knurled dial, on the same face as the on/off switch.  I haven't bothered to check any voltages, I'm a tune-to-taste person, coming from some other VV that also use the simple wheel type interface.
The firing switch is a pleasure, large, clean, firm depress to activate it, it falls naturally under a middle or ring finger, good position.
The catch cup is a good size, not huge but plenty big enough to pick up liquid from any rational feeding.
I really like the black case with no LED.  I don't need to know that the PV has power -- if I push the switch and get vapor I know it.
For batteries I'm using black trustfire flamejacket 14500, protected ICR.  These are the same ones I use in another good stacked 14500 VV PV.  I don't know OG's regulator design, but I vape at 8 - 10W typically (around 4.5 - 5V with a 2.5 ohm atty), and these batteries do well in that other PV.  With a stacked PV, the voltage provides much of the power, essentially your current draw is half that of a single-battery VV.  I'm not interested in testing ultimate power limits, but for classic 2.5 - 3 ohm atties or cartos this little PV will undoubtedly be nice.  If OG has a recommendation it should by all means be followed, these are just what I had at hand.
The feed works fine, a 3 ml bottom feed bottle.  The feed cutout is perhaps slightly small if someone has large fingers, but, after all, this is a 3ml feed bottle, inherently small.  Personally I find it easy to use, plenty good enough size for my hands.
With my IO6 atty this is overall just a pleasure to use.  I've got a much larger 18650 fixed voltage wooden feeder, an all-metal VV top feeder, and a tube VV with carto tank.  The OG is lighter than the other units, a fine performer, nice to have when I don't want to tote the bigger gear around.
It is a plastic case box mod, but it is cleanly built, an excellent value for someone wanting both VV and bottom feed.
Nice job 
