I would put feedly in the category of Reeder and Pulse, in that you can view all the posts from a specific site or group of sites one by one, nothing missing.So you'd say, to put it simple, that Flipboard and Feedly shoud be used when I want to read news about a subject (for example, "apple", or "tech" from different sites), and Reeder and Pulse when I want to read news from a specific site?
Whereas Flipboard is more of an roundup of tech/apple/science/fashion centric news regardless of the source of the news, as long as it's popular it's up there. Not to mention the twitter and facebook integration, showing you anything grabbed from whatever your friends posted. They're different markets all-together imo, and until Flipboard has RSS-centric features as feedly or reeder do, it'll stay that way.