I agree, Zedge is good. You don't even need the app--I've downloaded ringtones from their website on my computer, then copied the file over to the phone's Ringtones or Notifications directory via USB.
Do they sound as loud that way? Every phone I have tried this with in the past has had trouble matching the volume level of the stock ring tone sounds. Now I have my new S7 and find the selection rather lacking so once again I am on the hunt for ring tones.