Oh how I dearly love this game. It's not perfect, there are definite flaws, but overall I find it a great addition to my library.
On the plus side: graphically beautiful, with photo-real settings in monochrome with occasional bright dashes of color that really enunciate the scenes. Character graphics may be considered a little dated now, but nothing terrible. Music and sound work well. Voice acting overall is good and believable with the exception of Nigel, who has a sort of strange Shatnerian pace to his lines which could also be the result of botched sound editing rather than strange voice acting. I've heard people complain that the voice acting is bland overall, but I disagree; I like that the characters have believable tone and cadence rather than hamming it up (melodrama ruins immersion).
The biggest plus is naturally the story, which is deep and compelling and doesn't spoon-feed information. There is a lot of opportunity for the player to form their own theories and explanations for some of the strange events; however, if you are the type that prefers definitive black-and-white explanations, you may be frustrated by some of the questions that are only loosely addressed and left to you to form your own opinions on.
The ghost-hunting part of the game with a full Ghost Hunters set of equipment is really fun in my opinion, but I also suck up episodes of GH and Ghost Adventures like some people drink water, so I could be biased there. I really enjoyed snapping pictures and listening to EVP playbacks, which ranged from blatant clues to added plot points.
The neutrals: the pace is slow. The story, like many point-and-click adventure games, doesn't rely on fast action and jumpscares to progress. Rather, it slowly builds the story (and substories) into a cohesive narrative. I don't find the pace too slow, personally, as I prefer having the crap scared out of me in a slow, chilling way instead of a jumpscares-constantly-cause-startling-people-is-fun way. However, if you like fast action and immediate gratification, you may not like this one.
The negatives: going back to pace, your player character, Nigel, moves GLACIALLY slowly. There is a doubleclick-to-move-faster option that works most of the time, but you do have to wait for him to get "in position" on each screen before moving to the next even with the doubleclick. Since this game utilizes a fairly huge game world, this gets irritating relatively quickly. For me personally, it doesn't break the game, it's just an annoyance to keep in mind.
Some puzzles, as in most point-and-click games, are not as intuitive as you might want, but if you're a fan of the genre, you won't have too much trouble. Puzzles are definitely less abstract than some other games I've played.
The other complaint I see is about the broken achievements; while most work, there are a handful that only work in the German language version of the game. There are directions in the forums for how to access these achievements with a minimum of fuss if you're a crazed achievement hunter (like me!). While this is a definite negative, it does not in any way impact actual gameplay, and won't affect you at all if you're not "into" achievements.
So overall, I recommend the game. The negatives aren't negative enough to overwhelm all the positives, and the $10 asking price is completely reasonable given the substantial depth and length of the game. I've played through twice since purchasing and will likely return to it again in the future for my scary, ghost-hunting fix.