Just finished (Platinum).
I have to say, overall I found it quite disappointing, which is frustrating given that I greatly enjoyed the first Corpse Party, and to a lesser extent, Book of Shadows.
Unfortunately, much of it has to do with technical issues and gameplay design. The framerate is generally horrible, and stutters non-stop, especially when using the flashlight. The loading is atrocious, especially since it occurs every time you pause/bring up the menu (bringing back painful memories of Final Fantasy Anthology/Chronicles on PSOne). Regarding the gameplay, the inclusion of obstacles is frustrating, not challenging or scary. The chasing shadows are equally as frustrating, and are only interesting from a plot perspective (which is only mentioned at the end).
Honestly, I felt that the plot was unnecessary; the Heavenly Host story was self-contained and resolved, for the most part. Book of Shadows expanded on some plot points and added new perspective. To make a poor analogy, Blood Drive is like the Matrix sequels, expanding the scope to something that is less intimate, more bombastic, and IMO less interesting (and less scary); a bit deus ex machina. The new characters sure don't help, with their fairly ridiculous designs, constant swearing and misplaced sexual characterization (Kuon toward Satoshi, Magari's outfit). I guess that's a prudish complaint, but it just seems so out-of-place compared to previous games (notwithstanding Seiko and her pooper).
Granted, there were some positive aspects. The voice acting is great, as per the past games, and the localization is top-notch. The numerous "Wrong Ends" are at least on par with previous entries, with some excellent descriptions. And, for all the negativity I heaped on the new characters and plot, I quite liked the story arc of both Ayumi and Aiko.