Multiple accounts are supported in Newsflow. You need to click the + button at the bottom left of Prefernces / Subscriptions to add a new account.
In case if you use RSS and you would like to switch to Feedly/Feedbin, you need to add a Feedly/Feedbin account first and then remove the RSS account
You can remove an account by secondary clicking (two finger or ctrl+click) on the account name on the sidebar, and select remove from the context menu.

rockysandstudio.com
Category: News, Feedly, Feedbin, RSS
Compatibility: MAC OS X Yosemite, El Capitan
Leaf: News Reader for Mac OS X (Yosemite, El Capitan)

Leaf is an amazing news reader for Mac OS X (Yosemite, El Capitan). Read, share, star and search news from all of your favourite websites by using a clean, intuitive, OS X Yosemite, El Capitan-style next generation interface. Leaf is supported feedly and feedbin. Feedly App for Mac OS X, Feedbin App for Mac OS X