Here is a short review on Choice Rebuildable atomizer.
The atomizer consist of 4 parts (bottom to top): 510 base connector with atomizer, small air control ring with 3 air holes (internal), middle body with 3 air holes, and a dripper.  The atomizer is stainless steel except for the dripper (I think).  A coil (with a tiny wick) comes built into the atomizer.
You can control the air flow by aligning 3 air holes on the body with the air control (open 3 for airy draw, close 2 1/2 for tight draw).  For an atomizer at this price, this is a good feature.  All the parts are held by 2 thin o-rings on the base and another set on the air ring.  Here is the problem #1; the middle body is heavy and thin o-rings do not hold the body firmly.  Once in a while, the body lifts up and some 
juice leaks.
The atomizer base has a cup which holds some 
juice.  Inconvenience#1; the included coil has a tiny wicks that cannot draw up 
juice from the cup.  I immediately replaced the coil with longer wick so that it can pickup juice from the cup.  Then I noticed that the holes in the posts are not parallel (YMMV).  This made a inserting a coil difficult because the coil became deformed (some hot spots).  I took a niddle nose piler and turned one of the post so that holes were parallel (they were press fitted).
As a dripping RB atomizer, it worked as advertised.  The coil, with 2 holes open and positioned infront of the coil, proudced good vaper and dimished throat hit.  Overall, it works.  I would probably replace the o-rings for better fit.