I’ve used Shapeways twice for 3D printing parts for models. I also had some custom brass etching done. For my limited needs it’s adequate. I would do the same for laser cutting. But I can see the appeal of having your own machine and experimenting with it, or having a business using it.
I highly recommend The Poisoner’s Handbook by Deborah Blum. It’s not a “how-to” but a history of the development of forensic science in New York City in the early 1900’s. Apparently murder by poison was difficult to solve up till then, when the chemical techniques were developed. Blum goes into some detail about them.
