Reeder is free since v4 will launch later this year. It works fine on Mac and iO...

Reeder is free since v4 will launch later this year. It works fine on Mac and iOS. You can use local RSS or things like Feedly. I just use local RSS. No syncing between Mac and iOS btw.

http://reederapp.com

edit: There is also the news that NetNewsWire is back to its original developer and will be released later this year: http://ranchero.com/netnewswire/