I tried to watch the Netflix one last year, and quit 5 minutes in. Everything about it was bad. Recorded the first ep of American Ripper, but deleted without watching after listening to the pod.
Devil in the White City was a good book, and I think that you were correct that placing Holmes in that context helps. Not only was it Chicago at the turn of the century, but all these people flooding into the city to work at/experience the World's Fair gave him the opportunity to do what he did more successfully than he might have been able to otherwise. I think the book also benefits from the fact that it isn't entirely focused on Holmes, giving you a break from the ick factor of what he did. Although, as an architect, I'm much more inclined to find the design and construction aspects of both the Fair and his "murder castle" much more interesting.
As far as the "America's first serial killer" title goes, I read a book called The Midnight Assassin which looked at a series of murders in Austin, TX in 1884-85. And of course newspapers back then tried to tie that to Jack the Ripper as well, saying he left Austin for London. At least that one fits a bit better with the whole organized/disorganized profile.