I agree with all the comments posted. A good dedicated RTA will give you so much better flavour and be cheaper to run. A word of warning though, in my experience RTA coils don't last as long as stock coils, especially if you vape sweet juices. And there is a learning curve that has to be overcome before you can build a coil and wick the RTA reliably.
Thanks for the info @ChrisS - although that's an interesting point regarding coil longevity. In general terms, would it really be worse than say 7-10 day life of my current Smok coils? I do have a bit of a sweet tooth, and tend to use 70/30 VG/PG juice. Does that make a difference?