Can't speak to EH, but I own an HCigar Kayfun 3.1 clone and a Taifun GT clone. They are surprisingly well built- the threads are well cut, no metal chatter marks (some slight marking on the deck below the terminals on each; however not pronounced and not sharp). Fit / finish I would rate 9 out of 10; the Kayfun, when screwed together, looks like a solid piece. You have to look hard to see the join lines and by feel..you can't tell it's not one piece. No galling when screwing the parts together. I recommend them and I'm picky.
The typical Kayfun drip tip had a slight, miniscule piece of metal visible inside the hole looking from the top-just inside. I took a toothpick and pressed it against it, came right off. Other than that, no sharp edges or stray metal shavings.
WHAT DOES kinda irk me; the Taifun came with extra O-rings, x2 for each one used, plus the ones installed. The Kayfun...NONE. The installed set only. It was a son-of-a-gun finding extras for the o-ring that fits inside the top cap and seals the chimney. I did find them however.
Taifun came with some ni-chrome wire (good for practicing IMO), some wicking material and the aforementioned two spare sets O-rings. The Kayfun came with a key-chain mini screwdriver, a wick with a sad little coil wrapped on it, a drip tip converter (so you can use a regular 510 style drip tip) and a nice semi-hard zippered case.
I'm vaping both- did plenty of research via You-Tube, this forum, etc., and using organic cotton for wicking material, 8/9 wraps of 28 Ga. Kanthal on a 2.4 mm rod (about 1.7 - 1.8 Ohms) they both vape perfectly. OH- I'm using 100% VG tobacco flavors.
Got the HCigar Taifun GT at a local vape shop; the Kayfun 3.1 HCigar from Adirondack Vapor, New York.
Hope this helped.
Brian