The perfect beginner friendly rba (in my opinion) would be the igo-W or the igo-L. These have the option of 2 or 3 post for dual coiling. But I really think these rba's are newbie friendly because it is one of the easiest to rebuild on, very simple, and is cheap! you can find them on fasttech for 6-8 dollars and free international shipping!
Agreed, I also like to recommend the clones of the Helios, Atomic, and my new favorite, the Mephisto RDAs.
I like these mainly for the ease of building on them, and the vape quality, airflow options, and cost (around 30-40 dollars on Ebay, cheaper on fast tech).
I just got the Igo- w and haven't had any problems so far. I've been loving the vapor production on the dual coil! Been blowing clouds all day and I like the size of the device. I use an astro mod and it matches up perfectly with the Igo w in 350 mode. Definitely recommend.