I also use Digg Reader, but it seems dead. No API, no recent improvements, gets super slow when you keep scrolling down... Almost a year later and we don't have anything that comes close to Google Reader's speed and usefulness!
True. It's actually not too bad for me but I only have a few feeds (maybe around 10) that I keep in it. After the demise of Google Reader I reduced how many I subscribed too.
I have hundreds of feeds. If I don't keep up reading several times a day, scrolling down becomes impossible due to the exponentially increasing slowness on both latest Chrome and Firefox, so, I can't really catch up with updates. Never ever had such issues on Google Reader!