Doug coil vs other rife machines

Hey all,
I'm back on this subject haha. I was researching Doug coil and other rife machines. It seems a lot of people have great results with the Doug coil. I know it has a limit as far as frequency ranges but it seems to be fine for Lyme and co infections.

Has anyone used the Doug coil and/or any rife machines like the gb4000?

Thanks :)