NewsBlur was a kludge when it worked and let you add more than 12 feeds. And Feedly was prepared for Google announcing the Reader shutdown. NewsBlur could be a strong contender for the next exodus when Reader finally goes dark, but it has a long way to go.
The rest are a bit weird, mobile-only, or don't know what they're going to do when the Reader API they depend on shuts down.
Personally, I like Feedly's UX. It's like an evolution of Reader. It's much smoother, and has a magazine view for feeds where it makes sense.
It's the most similar to Google Reader (except perhaps for theoldreader), easiest import (no import at all yet, just sync) and best published transition plans.
