Clean, simple and easy to use. BUT it needs a few things...

There should be the option of being able to lock it into a position (Bottom of screen). Pop up windows would be better than the drop. That way you can place it at the bottom of ur screen.
Also, if you hover over it or try to click and drag, it shouldnt move or stutter. Fix that and ill rate it 5 STARS!!!
Other than that, GREAT APP!!!

Gulihenki about RSS Ticker for Google Reader, v2.0.1