Way back in 2011, the windows phone review team reviewed the best windows phone RSS readers. Back then due to lack of developer internet, there were not many quality RSS aggregators but times have changed now.
Meet Feed Viewer, an RSS news aggregator for Windows Phone that lets you browse large amount of content quickly. Download size is just 1MB and the best part is that it is totally free.
The user interface is intuitive and clutter free. The Feed Viewer app catches the content of RSS feed so even if you are without any Internet connectivity, you will still be able to read the articles.
It is available for both desktop windows and windows phone.