Read some chapters of it, not all that impressed with it. And if rumors are to believed than Brynhildr's rushed ending was due to him having to get started on this one but if that is true or not I have no idea.
I've read up until ch20 hoping to get a lead on what the plot is going to be, so far it's been dissapointing to me. The art is good, and it shows how far he has come since elfen lied but the story isn't doing it or me, and the way that Youta is acting like a complete dick at times doesn't make him an enjoyable MC.
I personally think that main problem of that series is rather a fact that pacing is extremely slow. Story itself has strong potential, but chosen format of 18 pages per week (sometimes not even) can be little tiresome for people that are not interested in "primal attraction" of series.
Regarding Youta, I would definitely not call him "complete dick" for that he is still too kind and in many regards pretty similar to previous Okamoto's protagonist. Just this time Okamoto is trying to pull opposite direction than he tried with Murakami in regards of protagonist's interaction with girls.
Supposedly it picks up a little as some thing are happening ch 22 or 23 from what I've heard but not having seen those chapters translated yet I can't give my opinion on it. I'll just have to wait and see.
I watching series from raws. Chapter 24 was pretty much "epic finale" of first arc and 25 just kicked new arc. So hopefully something will finally start happening. But on other hand unfortunately, chapter 25 is also a good example how Okamoto can wasting time as whole chapter is nothing else that characters standing on same place and heroine having mental breakdown about how she can't be without protagonist for anymore.
Well, at very least chapter 22 shown, that Okamoto still knows his stuff pretty well. So chances for good story are pretty high. Just pacing of story progress and "action time" needs little more balance out.
Whether this ends with proper ending or axed ending is a question. Okamoto seems to have big problem with finding good timing for when ending his series. So far only Elfen Lied had proper ending. Everything else ended axed. So who knows.
Parallel Paradise is trash, is the worst manga created by Okamoto Rin, fulled of fanservice moments, bad history, and bad developed characters. Don't compare Brynhildr with that shit, its an insult to that manga.