My thoughts/opinions.... like everyone else said, use your preferences to guide you...
Between the Anyvape CVI and Vision VAMO..
The simplified buttons to quickly access an increase or decrease in voltage or wattage on the VAMO much easier to use... just this alone made me put down my ZMax which uses a similar menu system as the CVI. Of course, the CVI does have various colors available and two styles/looks.
Between the eVic and the VAMO...
I do like the screen, but I don't use the screen often. The twist knob for changing settings appears to make it easy but I'd have to use one to see if I liked it over ( or the same as ) the VAMO's simplified menu setup. Again when it comes to colors, the eVic currently has more options available than the VAMO. The downside that really kills it for me with the eVic is the limited amperage output to address overheating the unit.
All 3 units provide support for both 18350 and 18650 batteries... so that is a wash. The yet to be released Smoktech Telescoping ZMax is also one to consider and it will provide even more options for battery selections, of course it will still use the single button menu system that I don't care for as much.
I only wish the Robust would be released with VV/VW options and increase amperage output... then I'd have a smaller option for times that battery capacity isn't an issue... For now, I'll just have to be happy using a 18350 setup for those times.