I really like this extension and am currently using it on my own website. I really like how simple it is to set up and manage on both the front and back end. It comes with many configurable templates to suit various styles and isn't overly complicated. The front end looks beautiful with many different ways to display user votes. The support is also top notch and updates are frequent!
If you are looking for a simple yet elegant polling option, i'd go with this one.