I like very much QuiteRSS, previous i used RssOwl. In QRSS i miss feature show excerpt news content on notifications lik RssOwl. I use services like OLX, Gumtree. When I see news content in notification, I see prices i don't must click on news or open program fo reading. Add image from news to notifications is good idea too.
Unfortunately, this feature is not popular for our users, there are more priority tasks.