I started off with a Greensmoke and then quickly went to a VaporKing from Vapor4Life.com. Very good website, quick shipping, lots of flavor choices, good prices. I can't say that the Greensmoke was terrible, but it did have some things about it that were very serious cons. Very short battery life, limited cartridge flavors, no option of buying the juice to refill (not in the same flavors Greensmoke uses anyway, they have unique flavors), not many places to buy supplies from other than Greensmoke itself, and sometimes the quality control on their carts was terrible. The pros seemed to be a bigger vapor (when a cart was operating well) and the two piece system, of which the latter of the two can be accomplished elsewhere as well. Enough to send me to V4L.
For a beginner, I don't think you can go wrong with the V4L VaporKing. You can get all you need from that site. I would recommend getting some juice from them and the "PREMIUM" blank carts they sell. The premiums have a rubber stopper at the end the is VERY easy to pop off, which makes it very easy to refill. I actually use a pair of nail clippers, the curved part that is used to clean under finger nails is actually and awesome tool to just pop the top! By the way, if anyone from V4L is reading, I'd recommend adding a "top popper" tool to the site. I know you can grab pretty much anything in a pinch, especially with the premium carts, but hey, why not find the "ultimate" tool? Battery life is excellent, and there are a few different ways to charge (wall charge, usb charge, or car charge). I would recommend getting a usb passthru for the ultimate 808d-1 experience! I like the other batteries for when I'm on the go. Just bring a few carts and maybe some juice for quick refills and you are set. I prefer the manual batteries because I like to control my vaping--the more I read, the more it seems that the majority of people like the manual buttons as well, but I'm sure it is another aspect that is subjective.
All in all, I now have a Janty Stick V3, which is nice, and I'm still getting the hang of it because there is more involved in the 3 piece systems. I still use the V4L's for their portability and as backup if the Janty is empty or not quite functioning how I'd like. I switch back and forth. For ease of use, portability, battery life, options for suppliers, good vapor production, throat hit, and good taste, I'd recommend the VaporKing from V4L, a couple manual batteries and a usb pass thru. Get some juice and some blank carts as well and you're set for a while to enjoy the vaping experience. I do see some advantages to the three piece sets, but I tend to be someone that gets really excited and, well, obsessed with something new that I like, so I enjoy the searching and experimenting with different types.
Everything is subjective with vaping, which I'm sure more will agree, but that doesn't mean that there aren't certain models that will meet a persons subjective tastes better than others. You may have to just pick one and go with it to see what your vaping tastes are, then once you experience it, you will know what to look for and where to get it.
Best of luck!
P.S. I was a pack to pack and 1/2 per day smoker for about 15 years, never tried to quit before, but was off analogs in literally 3 days (would have actually been sooner but I didn't want to waste the remainder of a pack of cigarettes I had, haha!), and it was actually with the Greensmoke, which I don't like nearly as much as the others I have since purchased.