God this is a terrible answer, but for what it's worth, everyone's mileage is different. There's been units I couldn't stand that others have loved and vice versa. When I started more than 2 years ago I found myself complaining that some ecigs had too light a draw and other's too hard. It's such a personal decision. That being said much of my initial investment was trying a lot of different ecigs until I settled on one (which actually ended up being the first one I bought.)
One good thing you'll find on here is a fair measure of quality and consistency, beyond that personal choice becomes the standard. As someone who has fallen off the wagon some time ago and just getting back into vaping I'd say you've picked a terrific time as the technology and choices are so superior to what was just a short while ago.
Ditto everyone's comments on your service Sgt! Heal well and welcome to the forum.