I used Citation Machine regularly when I was taking my Masters classes. One son uses it for his undergraduate classes and the other for high school assignments. Rather than dreading making my bibliography like I used to and procrastinating until the very end, I now start it first using CM and add resources to it as I use each new resource. The APA Handbook was always on my computer desk as I wrote my thesis and was checked constantly.
I have introduced CM to teachers and students at my high schoool over the last year and a half. Many teachers are delighted to have students use it. However, there is a core group of teachers who say students should have to learn how to make a bibliography from scratch. I don't personally believe students need to learn all the formating and punctuation. What they do need to learn is to respect copyright and cite their sources. They are far more likely to do this if they have a user friendly tool like CM.
I notice that many resources, especially online ones, provide a formatted citation for use. I like CM instead because you can choose APA or MLA style, it offers many different types of print and non print resources. It will also generate a citation even if you don't fill in all the spaces or if some of the information is missing.
In order to use citation generators like CM, students still need to be able to find the needed information on the title page or verso of books. Other forms of print resources like magazines and encyclopedias are more challenging but if the generator is used it prompts them what to look for and how to type it in (example: author first initial. only) Non print resources present their own challenges. Students need to be taught how to truncate, find home pages, read the "about us" pages, etc. to find copyright info like dates and authors. Another huge advantage of copyright generators like CM is that it is simple to copy and paste long, complicated URLs directly into the format.
I find Citation Machine an excellent tool and have encouraged students to use it by linking it to my library website.