Strange--I have been using Newsblur since GReader closed, and am impressed at how fast it is. There were a couple of brief periods when it was sluggish, but he's done a good job of clearing bottlenecks as they have come up.
FWIW, I have about 400 feeds and about 1000 articles a day, so I am using it fairly hard.
Gotta jump in here and agree with the other sub-commenters — it's generally very responsive. I mean, it has its once-in-a-while hiccups just like every other service out there, but overall, very very happy with it.
