I have been a RSSOwl user for over five years. I have tried QuiteRSS and like it for its speed and its ease of use.
But one feature will stop me moving to from RSSOwl to QuiteRSS is "Saved Searches". They are not filters. I keep two folders for Saved Searches (one for work and one for interests) used to search for keywords across different folders of feeds. Each Saved Search looks for different keywords across the entire article in different combinations of folders. Each Saved Search looks like a feed itself and an article "read" in the Saved Search is also marked "read" in the feed (inlcuding duplicate articles). I have also grouped Saved Searches in folders so I can see all searches or click on one Saved Search at just articles of that search.
Is there a Saved Search feature planned for QuiteRSS? With the large number of feeds I use, I cannot be without it.