I’ve been using the OS version of the RSS feed reader Reeder for a long time. I probably would have used the iOS version more if I could have easily synced the feeds between devices, but I would have had to set up another account to do that and I just couldn’t be bothered to figure that out.
The latest version of both apps now support iCloud syncing, and it works perfectly. Reeder was stuck at version 3 for a long time and it looked like it might just fade away, but there have been two updates in the past year or so. A lovely simple app.