My favorite atomizer/RDA/RSA is the B2K, I have 4 versions, the KRNK version, the Caviar version, the v4 and v5. I really like a postless deck, for me it's the easiest way to build. I also really love all the different cap and ring options, so many ways to customize your RDA. It's like having several rda's in one. AND THE FLAVOR! Man I sure love love the flavor with the b2k RDA.
And all the popular after market cap manufacturers make caps for it also. I've tried the NN caps, but the Squonk Donkey b2k cap improves the vaping experience dramatically. I have 6 Squonk Donkey b2k caps, different colors and with Beauty rings and drip all made and designed by Tyler Hargrove. I can't say enough good things about Squonk Donkey and their Caps!! Here is a picture of some Squonk Donkey b2k caps.