Here are some other impressions from 3d printing with this filament.
The filament diameter measures 1.75 mm spot on, thumbs up BlackMagic3D.
It prints very well with a nozzle diameter of 0.5 mm. I like the quality, and the lack of stringing.
Surface texture is rough, with shiny black surface (it somewhat resembles that of ferrites, or of an iron rod heavily oxidized by heating in air, or packages of integrated circuits). It's a pleasure to touch.
The printout is not particularly heavy. It is heavier than normal PLA, but not much.
I had some problems with sticking to glass. First time it went perfectly, but second time it peeled off like hell. I don't know what happened, but wiping glass with acetone helped.
My printouts were small to say anything about warping, but those small prints did not suffer any delamination due to warping.
As for attraction to magnets. It is attracted. But ferrites beat it by a large margin. And bulk iron gets even much stronger attraction than ferrites. So... yes, it, attracts, but I struggle to find any real use for the filament.