Isn't it better to use something invalid (like 0.0.0.0) instead of 127.0.0.1? If you have a development server on your machine, rerouting ads to 127.0.0.1 means lots of useless requests...
I use this as well (The zero version) but I wonder if there are any performance hits from doing this. I would think not but I've had sites (on desktop and mobile) lock up while waiting for something to load. Most of the time I assume this is some scrolling or "navigation" plugin that hasn't loaded yet (and not ads) but I'd love to read an analysis on hosts vs adblock vs µBlock.
it's not as elegant as hiding the HTML elements, you see some question marks on the page if safari couldn't load the resource. but overall i'm pretty pleased and it gets the job done.
http://someonewhocares.org/hosts