Please note, there are actually 8 volumes for Ray - 7 sequential volumes and one "+" volume with several sidestories, an appearance from Black Jack, and a test run chapter of the author's Gate Runner. I have adjusted the volume list accordingly.
What to say about Ray? I finished the last of the 8 volumes last night in the original Japanese, and as there are currently no comments (likely due to the lack of a complete scanlation) I felt obligated to say something.
First, a caveat, despite the gas-mask baddie on the cover holding a pistol, there is little to no gunplay in this manga. Ray centers around "Rei" (in JPN), a young and highly skilled surgeon at a very unusual hospital who just happens to have x-ray vision.
The first ~3 volumes all primarily feature unrelated vignettes in each chapter, such that the real overarching plot does not begin moving until probably book four. While the grand scheme does have some nice twists, in my opinion it builds up too slowly, and then wraps up far too quickly - resolving itself almost entirely in only book seven. Looking back I feel the isolated mini-stories were more entertaining than the main conspiracy.
It should also be said that unless you are an indecisive 13 year old girl, Rei will frustrate you immensely as she hems and haws over a love triangle that isn't resolved until virtually the last page when any sane person could have chosen the appropriate outcome almost immediately. (note that I'm 24 as I write this, adjust your viewpoint accordingly...)
The art style is what I'd call stylishly realistic. These are not your normal manga characters, backgrounds are well-detailed depictions of daily life in Japan (I should know, I lived there for 2 years...) and the characters look like, well, real people. You will not find any of the standard manga conventions such as bloody noses and the like used to explain emotions here.
I enjoyed Ray (Rei), and the plot was interesting enough to keep me reading until the end, but if I ever revisit it it will likely only be for the short stories in the first few volumes.
Weak sci-fi meets hospital meets love triangle,
6/10
-Shad
PS - if you have any questions about Ray I would be happy to discuss the series, so please drop me a line via private message...