RSS queries

As many of you know I am anti-RSS but I would like to understand the phenomenon better.  So I have a few questions for you.  What feature in an RSS reader do you not have but long for?  What would cause you to switch from one reader to another?  Would you ever consider a reader that forced ads on you, bundled up with the delivered post?

Don’t worry, we’re not planning or even contemplating changes in our RSS feed, I simply would like to learn.