I love this app and use it regularly. The only thing Id add to it is the ability to back up to iCloud or Dropbox (or some other cloud storage service). I recently got a new iPhone, and when I restored my old phones content on the new phone, the Recur! app restored, but its data didnt, forcing me to go back into my old phone, write down all the items and manually re-add them to the new phone (very time-consuming if you have a lot of items). Otherwise, terrific app!
JurassicSnark about Recur! The Reverse To-Do List, v1.1