I liked this RTA. the steam is a little hot for me. but I found the temperature I wanted using thin wire. flavor is very good, the throat hit is also sufficient. very easy to use. 4x0.6 mm too tight and low flavor. 6x0.6mm is best choice for me.
i am using ulton clone. only fault is the o-ring. the o-ring at the base of the chimney is bad quality, too soft. I replaced it with another o-ring and now it's fine.
I really liked the Sputnik. I usually use it with tobacco flavor liquids. It is compatible with my liquids and I am satisfied with their deliciousness.
Draw is perfect with 6x0.6mm disk for me.
I've got the SXK version and I think there's a problem with the air disk. It looks like the holes are smaller than should be and so the draw feels tighter than the alleged 1.2mm claimed. Have ordered the other air disks to see if they are any better. They are on the way. So it looks like the Ulton clone is the way to go.
I got the SXK version, set it up with 1ohm 28awg kanthal coil, 6*0.6mm air holes, draw is very smooth and quiet, tried a new liquid and the flavor is intense. Not sure if that is from the RTA or the juice so I am gonna have to wait and try another liquid before I can share my experience. Overall it has been a pleasurable experience.
Finally got the extra air disks for the Sputnik. Think I've got the 6 x 0.8mm one in. Draw is great for me and flavour is really good with Manabush Tribute Chiri. Will try a fruity flavour next. @rj267 this is definitely worth considering imo.