I feel like I kinda have to warn people that plan on buying the Robbot version.
Got mine 2 days ago from focalecig. I read great things about the Amod/Wotofo version but that one wasn't available anymore. Figured since the Robbot version is actually more expensive it can't possibly be worse. I was wrong.
Here's a picture comparison of the chip housing from the back (battery tube removed):
Amod/Wotofo
Robbot
Take note of the sloppy machining on the plastic cover, also the (steel?) positive contact screw as opposed to the copper screw on the Amod.
The actual chip perfomance however is the worst part. It works perfectly well until about 3.2V left in the battery. At this point the graphic battery indicator has just passed the halfway point. From there on it starts crashing down hard. It simply can't keep up the regulated wattage from there on.
I'm used to dodgy performance from clone chips by now, but this is one of the more disappointing ones.
Just a heads up.