I like the iOS client Unread for this. You can set it feed by feed to either display the feed content as-is or have it parse each article reader-mode slash Inst

I like the iOS client Unread for this. You can set it feed by feed to either display the feed content as-is or have it parse each article reader-mode slash Instapaper style and show that instead of the feed text I imagine others do this too, keep an eye out for it as a feature! Very handy :)