The best thing about the Merlin is the offset posts for SINGLE COIL building, which I prefer. I have been unable to find another RTA with offset posts. Since I wanted to find a similar but different brand RTA, I did a bunch of research. There are of course many dual coil RTA's out there, many seem built for high wattage, cloud production. Not for me as a restrictive lung or wider airflow MTL vaper, that likes flavor over clouds. I don't like Genesis style tanks, so I excluded that category.
I settled on the new Aromamizer Supreme Lite. Always heard great things about Aromamizer tanks, but didn't like the early versions with the rubber AFC band.
This is also a dual coil build deck, does come with the PLUGS to block juice and air, to build a single coil. But, you can run a single coil in between the posts, and not use the plug!
Unlike the Merlin, there is no top fill cap oring that falls out.
But regardless if you like JFC or not, the way they did it, is amazing. Granted, the juice is routed to the bottom of the Atty, then comes up from the bottom, so they could design a blade type system that closes completely. You can close the JFC, take the build deck out, hold the atty right side up, and no juice comes out.
Sure I wish it had the Merlins offset posts, but there is NO press fittings here, you can take the whole thing apart. If you get tired of tinkering with the leaky Merlin, check out some video reviews of the Aromamizer Supreme Lite, it's the closet thing I could find for the type of vaping I enjoy.
FWIW: I have yet to have any leaking on my black Merlin with notch coil and the rayon wicking, condensation is acceptable as almost all tanks have it in various degrees, but if and when the LEAKY day comes, it goes in the trash. I'll tinker to a degree, but when my hammer comes out, it's not for fixing!