I'm no expert (been vaping for about 6 weeks) but I thought I'd try my best to help you out. My personal suggestion is to rate for yourself what is most important to your smoking enjoyment. Everyone is different and most don't find the e-cig for them on the first try. You will be have to be willing to work at it, experiment, spend money, and be patient. Once you've made a guess of what you think is most important, you can start reading peoples' reviews and make a better decision.
The big factors for you to consider are:
Looks - Some MUST have the e-cig look as much like a real cig as possible. If that's so, then that limits you a bit but there's still a decent amount out there to choose from. You could always go for something not so much like a real cig for when you're not in public and only use the real cig clone when you're out and about.
Flavor - If you need it to taste exactly like a real cig, you won't find that. Some give you hints but all flavors from all companies have a sweet tinge to it. Some more than others but the sweetness is there. Some are put off by that. I found that even though I hate fruity flavors, they go well with the liquid base.
Throat Hit - Some people care about the throat hit (the "tickle" or irritation at the back of the throat when inhaling). Regular e-cigs differ quite a bit but the liquid and flavor you choose has a lot to do with it. The higher the voltage of the e-cig, typically, the more throat hit as well... and the less flavor.
Vapor - This depends, again, not only on the e-cig model but on the liquid too. Higher voltage mods contribute a ton but you're usually gaining more intense throat-hit and less flavor.
Consistency per drag - Meaning the same flavor, throat-hit, and vapor every time. Many say that the only way to achieve this is through a battery mod. I would agree, though, I've only ever tried one battery mod.
Battery Life - Most stock e-cig batts don't last very long (anywhere from 1 - 5 hours depending on model and vaping habits). The only way to really get good battery life out of your e-cig is to use a non-standard looking e-cig (a battery mod). A few commercial examples are the ScrewDriver, Janty Stick, and Prodigy.
Atomizer Life - This is mostly contributed not by e-cig but by the liquid you use (some flavorings coat the atomizer much more heavily reducing their life) and how you vape (i.e. vaping for 5+ min constant or less frequent intervals between vaping sessions). VG is said to reduce atomizer life as well (though I have never used it so can't say from experience).
Using E-Liquid - Some don't want to mess with buying liquid and filling carts. There's a few models out there that come with "cartomizers" which means the cartridge filled with nic juice and the atomizer are in one section. They are disposable and you just put on a new one when you want. You *can* refill them with liquid if you want but it really doesn't work all that great. Going this route will not be cheap. The carts are decently expensive. You can also go with models meant for refilling the carts but just buy pre-filled carts. This is still much more expensive than filling them yourself but if you don't want the mess, then it's an option.
How long a filled cart lasts - Some put importance on how *much* liquid a cart can hold but that doesn't mean jack... It's how long it lasts before it starts tasting like sh*t or just not getting enough flavor/throat-hit/vapor. Sure, some carts can hold .5 ml, 1 ml... but most that hold that much will still be half full when you need to refill. If you decide to use liquid, it's not a super huge deal as you'll probably carry a small bottle around with you but if you're having to top off a cart after every 10-20 puffs, that gets pretty annoying.
As for the most popular e-cigs on this forum, it seems to me that the 801, 901, 510, and ScrewDriver and the most popular. Hope this helps... Probably long but I did it more for me than you as I need an excuse to take a break from my packing (moving to a new apt!). I know, I'm selfish
2+ packs a day for 30 years, and I had tried everything.
