I just started
vaping recently, so I can't tell you about the pro's and con's of every device but here are the few that I have heard good things about.
I personally chose the M601/M602. Got a good deal (afaik) from electronic-cigz.com. Customer service is excellent, product is fantastic imo. Does what I wanted an e-cig to do. There are of course a few things that it lacks, but that's across the board unless you mod your own apparently. Longer battery life (I've heard this model has a good life).. longer cartridge life (again, I've heard this one is "ok")... longer atomizer life (Honestly couldn't tell you, had mine for almost 5 days now and they're still going). Also you get 2 vials of e-
juice. Tennessee Cured tobacco flavor is very tasty imo. Don't know many other flavors but I'm sure I'll continue to use this one.
I've heard that people like the 510 for its portability. So you might want to check into that.
Janty Stick... heard good things, but it doesn't look/feel like a cigarette. You might not care about that, I did. (Maybe I'll look into one later)
MoobyGhost and SuperVaporBros do
reviews on youtube so you can get a good idea of what you want by doing a bit more research.
If I had to do it over again, I might have gone with the M401 because they have a USB passthrough and as I spend the majority of my free time on a computer, it'd be perfect. However, Sean said they'll have a M601 passthrough soon. Either way, you could get a passthrough and have atomizers for that and also have atomizers for your portable, whichever device you choose.
There are some threads devoted to (Which device should I get?) on this site, check those out as well. Good Luck finding what you want ^.^