Not so much scary, as moderately creepy. Most of the entries consist of summaries of tour parties where someone fainted and/or came away with scratches/bruises from being "touched" by an entity in the haunted mausoleum, with little variation; although, there were a couple of stories of activity in the building immediately adjacent to MacKenzie's crypt; those began after the crypt was disturbed by an intruder in 1999.
I would be more interested in reports from psychics giving specifics of their findings, than repeated description of manifestations.
I didn't like this book so much. I found it quite boring and horribly drawn out. I did NOT find it terribly believable. I personally enjoy the compilation style books with lots of true ghostly encounters.