I have always wondered about the benefits and have never heard an a-b comparison. Maybe the question is -- At a particular price point, do you want some of your money invested in rear firing tweeters vs having that money spent on some other aspect of the speaker. The 'less is more' argument, particularly if they are usually switched off.
rear firing tweeters....
I have a pair of old Snells with rear firing tweeters...just curious why we don't see this configuration more today ? Phase issues? Placement problems? Engineering issues?