To be honest I'm still kinda confused because I don't know all the terms Pigs used but it sounded kinda cool.
For me it was very simple, the original Rev 3 was just plain cool looking. I have around a dozen of them, I still use my Rev 3's. They are awesome, but it is getting hard to find the batteries for them, they use 2 - 16340's. I mostly use a classic Billet bridge that uses Aspire BVC coils, those are the only drop in coils that I use in any devise, I vape MTL and they are fine for me.
I currently carry 2 Rev 4's to work with me, and I like them because they are very compact, with no tank on top. Easy to just drop in your pocket and go. I do look at the new rebuildable's for them, but just never found one that I like. There is also the fact that the original BB is made in the USA. There is a ton of different atty's for them now, and it can be very confusing. Most of all the new Billet Bridge's and Atty's are geared towards DL, so there are a lot of options. MTL
vaping, not so much. The original is expensive, but I personally think they are worth it.
KAS