haven't tried greensmoke, they seem a little expensive but they have good quality stuff it seems....
my first ecig was the ego-t and i love it....its so easy to refill, the battery lasts me at least one full day sometimes two days... the starter kits cost about $60-$70 by themselves, then add about $20-$30 for eJuice... so about $100 including postage... the only problem with it is sometimes it leaks a little.... but the vapour and usage u get from a single charge is absolutely amazing... you could also go for a 510 (which i think is what greensmoke units are based on) but the battery lasts equivalent of under 10 smokes rather than about 50 smokes for an ego-t battery, 510s give good vapour , are smaller and look like a regular cigarette (which i dont like, attract more unwanted attention when vaping in a non smoking area) but you will be changing batteries regularly and may need to buy a PCC (personal charging case) to carry around to recharge bats on the go!
no matter which ecig you go for, they are never exactly like traditional cigarettes (analogues), it will take a little getting used to, some people still smoke an occassional analogue while making the transition, i did... but as you get used to the nice flavour of an ecig, the analogues start to taste disgusting compared to an ecig...
if you want the ecig to have a similar throat hit (burn) to an analogue then you should start with high strength nicotine, say approximately 16mg - 24mg
anyway good luck with this, wish you all the best!