I don't experience any unresponsiveness when downloading. It may take slightly longer to fetch the feed if you have a slow internet connection, but other than that, I don't see any problem. The only unresponsiveness I get is when the list of items gets quite large. The scrolling becomes a little 'sticky', and it takes a split second longer to respond to screen taps on the list items. I don't know if there's a solution to this. I'm considering reworking the UI using QML in future, so I'll look at this in more detail at that point.