I have ego, ego tank, and riva...brb phone dying
...ok sorry. My ego is 3.7V (650mAh), I ordered the 3.7 and the 5v from Godzilla. I wanted the 3.7 for the clear dual cartos because they're just...well awesome. And there is a huge difference between the egos and the 3.7 as far as vapor, and flavor.
This was my first 5v BUT I have veteran vaping friends w/mods that cost a car payment and they all recommended this box mod, they have these too! I'm using a 3 ohm carto (been through clearomizers, ego tanks, carts, attys, smart carts, dripping etc, etc) and this hits just right. I use KBV joose which is great stuff, but only once I got the 5v did I realize that not only was there such thing as a warm vape (not the hot burnt carto kind of warm, lol) but I can now taste all the delicate layers of the e liquids.
This box is well made by a good guy at a steal price. If you're looking to test the HV waters this is the box to do it with, IMHO.

oh...and it's super easy to use and the batteries last all day.
HTH~Hope to see you around..renee