I'll play...
The Biochip is great. Near impossible to over squonk, good flavor, easy to build, and doesn't get hot, even at 35w, and a very unique design.
The Mjolnir is a flavor chasers dream, and I love the drip tip, a narrow bore, tall, unpolished 810.: It brought out flavors in my juices like no other, it is on the tall side though...
Right now I'm using the axial with the clear PC cap on both my current mods, single and dual coil, ~0.20 ohm each. Massive post holes, and easy to build.
The RDA that I'd say I used most, until I got a recurve, was the Dead Rabbit SQ. The squonk system sucked juice back no matter the angle, as there are squonk holes in the juice wells, and the air flow was designed in such a way that you can basically saturate the coil with a heavy two finger press, then return all the excess. Only downside is that the flavor is only there with a 3.5mm coil or bigger.