Another option for a high-end MTL RTA........... KHW Mods
Dvarw MTL FL. I have a couple, they are excellent MTL RTA's. Very comparable to a Kayfun Prime or KFL.
Nice thing about the Dvarw is the number of available
AF inserts. One can have a "true" MTL to a very airy MTL (or an RDL).
I have one setup for MTL and the other setup for an airy MTL to a tight RDL.
Also have a Dvarw DL setup for more of a "tweener" between RDL and DL.
How would I compare a Kayfun to a Dvarw? Each offers excellent flavor. I would give the nod to the Dvarw's for being very easy to build on and wick. Some people find Kayfun's to be difficult to build on and wick. Wicking on Kayfun's is a challenge for some people. I find Kayfun's easy to build/wick. The Dvarw's and KFL's are bottom fill RTA's. The Prime and K5's are topfill with JFC (juice flow control).
I always have a Kayfun and a Dvarw in my normal rotation.