In my experiences so far I'm finding that working with the 28awg ni200 is kind of a pain in the ...., the metal is just too soft. The best
coils I can make with it are micro
coils around 12-13 wraps around a 1/8" microdriver, which I don't particularly like because they get gunk all over them very quickly and there's no feasible way to clean it off. I've had mixed results getting the temp control to work properly. Right now I have a Kayfun with twisted 30awg ni200 and it ohm's out at .12. I have temp set for 430 degrees but it never goes above 360-370 degrees @ 21 watts so temp protection never kicks in. I still get a satisfying vape but I'm far from mastering a good ni200 build on a Kayfun. This has also happened with non-twisted builds as well. My other Kayfun I just tossed in a 5 or 6 wrap 28awg Kanthal spaced coil and ohm's in at 1.2 @ 21 watts and I am getting a nice vape.
I've stated before that the device is awesome, build quality is great, form factor is great, reverse batt protection is a must and also great, ability to swap batts on the fly is painless and requires no tools. Work's excellent with standard Kanthal builds but I'm not entirely happy with ni200 building just yet. I don't regret the purchase because having a nice regulated device that has a wide range is excellent.