I watched Nurse Witch Komugi-chan (all of the original material). I watched the first 4 episodes of R and then dropped it. Note: I have not seen more than like 10 minutes of Soultaker.
The originals are great. Simply put, they are funny and entertaining. Good voice acting too. Most importantly, they have tremendous cultural value. If you're into "otaku culture" then I strongly recommend watching Nurse Witch Komugi-chan Magikarte. It won't even take you long (there's like 8 episodes). Overall 7/10 but don't let that dissuade you. That's just an intellectually honest rating; I'm still really glad I didn't pass on the series. The series is highly underappreciated (this decade at least), and I strongly urge you to give it a chance.
Okay now on to the 2016 'reboot'. I'm not aware of the legal issues or licensing process and all that, but I'd imagine there's a story to be told there. Maybe someone can enlighten me on that. As you might infer from me dropping it, Nurse Witch Komugi-chan R is awful compared to the original. It is unfunny and not entertaining. The art style is nauseating. There are some cute idol song cutscenes, which I'm a huge sucker for (the CG isn't even that bad in this case), but that's not enough to get me to sit through the entire series. Every aspect of it is really just bad. I went into it with a positive optimistic attitude too.
Not much more to say. Again, I think you should check out the original Nurse Witch Komugi-chan if you haven't seen it. It is underappreciated.