Cluster,
I would not call the vapor harsh, they produce good tasty vapor with a good enough hit that this 32 yr Marlboro/Camel man has no complaints. As far as cost, the initial cost is slightly higher but still way less than tobacco cigarettes, if you could afford to smoke tobacco cigarettes you can easily afford the 2pc units. Contrary to noob belief, not an insult either I was once a noob myself, the cartomizer carts are refillable and in fact are easier and cleaner to refill than 3 pc units. The cost when refilling your own is comparable to the 3 pc models the difference being minimal and not worth arguing about, as I said if you can afford to smoke tobacco cigarettes you can easily afford these. As for the juice being "leftover" I have found that they wick up pretty much all the juice. The 510 or m401 that I have used leave more than the carts. The number of times you can refill them is not set in stone. Some people have had them last for over 10 refills so we can't really say anything definite so once again, not worth arguing about.
I have bought the m401, the 510, a mod for the 510, did all the little tricks. Then I looked back at my first choice of the KR808D-1 and got it. I was not disappointed. You can call me a shill all you want, I have been down the road many of you are traveling now, and I know the differences first hand not from word of mouth. I speak from experience and you throw "they say" at me and call me a shill? Did you bother to think that I don't want to see others waste $150 looking for something they can buy the first time around? If you want to play with your E-Cig modding it out to work decent, and all the other crap that goes with 3 piece units then more power to you, some people like to play with their toys. I am not one of those people, I spend the cash I expect it to work well. Taste is subjective, what I call harsh on the 510 many people call throat hit.
I would love to see a poll to see how many people bought a cartomizer first and then went to a 510, 901, m401 or some other model because they weren't happy with it, and a poll for how many of those 3pc owners went to the cartomizer because the 3pc models didn't cut it. I would be willing to bet that the numbers for the first question are pretty low compared to the second question. All in all it's subjective to individual taste. As for having someone read my advice and not be happy, I can live with it since they are also asking for opinions. I am not holding a gun to anyone's head and saying buy it or else, I relate my experience and my point of view they can take it or leave it.