The article says free with IAP is making much more revenue. You'd probably be wise to try that with yours.
one struggle i had was what to make free and what to charge for. i thought about making the app free and charge only to export data, but i felt like people might feel duped by not realizing and then be forced to pay when they thought it was free. the plan with limiting the # of entries makes way more sense.
Supertop's Unread also has a great (similar) take on IAP: https://itunes.apple.com/us/app/unread-rss-news-reader/id911...