I've used the Kanger Subtank and the Atlantis and have to say that the Kanger seems to be more efficient. At the same wattage, using the supplied .5 ohm coils in both, the Kanger gives me a better vape - more vapor and flavor. I have to jack up the wattage on the Atlantis to get the same vape as the Kanger tank.
Also, to the op, rebuilding a single coil dripping atomizer is actually easier than building a single coil RTA, at least to me. It's not getting the coil right, but with the dripper you never have to worry about the wick tails in the juice channels, out of the juice channels, too short, too long, not cut properly, not feathered properly - these are all of the various terms I've seen and read about here in discussions about various RTAs.
I have had very good luck with single coil Kayfun style RTA's like the Kayfun and Lemo, but a dripping atty is even easier to master.
If I were going to recommend an RTA to a relatively new vaper, I would say to go with a Kanger Sub Mini. It gives you the option of using the pre-made coils at .5 or 1.2 ohms and you also get an RBA. It may not be a true cloud chaser's dream, but I can fog up a small room pretty god with mine even though that really isn't my goal.