Takahashi-sensei's works are a bit of a hit or miss for me. I loved Mermaid Saga, Inuyasha was okay, and Ranma was some of the stupidest drivel I've ever read. Rinne falls somewhere around Inuyasha on the continuum, I would hazard. I've finished nearly one hundred chapters of this manga, and I'm still looking for a plot. Thus far the series has been completely episodic: a supernatural problem arises, and the main characters deal with it within, maybe, five chapters tops, and it is forgotten. There have been an endless number of characters introduced to bring these problems to thecast's attention, and then they're gone. They're plot devices, nothing more.
As for the main cast, they haven't grown much over those hundred chapters. Now, they are interesting characters, with strengths and foibles and problems, but none of those problems seem like they'll be solved anytime soon, or that they are even trying to overcome them. Rinne is still broke, and the love polygon is rather stable.
The art is instantly recognizable from the author's other works. While unique, it's not spectacular.
This isn't to say the manga isn't enjoyable. It's a pleasant enough diversion, but like cotton candy, it's lacking in substance. At the same point in Inuyasha we knew many of the major plot points of that manga. Rinne seems to be here for a long haul like so many other Takahashi works. It's certainly worth a little light reading, but you might find yourself wanting something with a little more meat.