Ranked in these QuestionsQuestion Ranking
Pro Doesn't consume cpu time or memory
The app updates the hosts file periodically but doesn't need to run in the background in order to block ads, which is especially convenient for older phones.
Pro System wide blocking
Use the hosts files to block ads, so it works for everything.
Con Needs root (by design)
Needs root to update the hosts file.
Con Won't block same domain ads
Because the host file can only redirect domains, if the ad and content are on the same domain the ad will be displayed.