For me it's all about the button--it's the part of your
mod that you'll be interacting with the most. Bottom button, bottom-side button, top-side botton? Short throw or long throw? Light action or firmer action? Etc, etc. Then comes battery tube configuration--telescoping or fixed length? Budget fits somewhere in there as well

. Once you figure those three things out, your field will narrow down.
As much as people throw around voltage drop numbers, I think the more important thing is how the
mod feels in your hand. You can tweak the builds of your atties until you get the vape you want: you can work around voltage drop that isn't best-in-class. There's no fixing a
mod that doesn't feel right in your hand when you hold it and use it.
I personally like bottom buttons with a short throw and a light action. I like my battery tubes in fixed lengths because tube wobble bothers me. My preferences are reflected in the mods I own: GP Paps 2.5, Super-T Simplicity 14500, an Atomo by Gilles, and a Paps X on the way. I also have a Super-T ELA on pre-order, and it's something of an anomaly in my lineup in that it's a telescoping mod, but my gut tells me I'm going to fall in love with it when it arrives.
If you're a fan of bottom-button mods, the button on the GP Paps is legendary--many a vaper has been ruined to other mods because of the button, myself included. And an SS version isn't terribly expensive @ $140 retail. I
really like me a GP. Wallet permitting, I'm going to try and get in on a Lux in the future.
I'm also really impressed with the Super-T Simplicity that I own. The button isn't as nice (to me) as the one on the Paps, but it feels good. I imagine that the button on an 18xxx Simplicity will feel very similar. It's very well made, and it's a pleasure to use.
Super-T and GP are the only mod makers that have seen repeat business from me, so I'm sure you can guess where my recommendations go
