I have been using GD Star Rating plugin for a long time. Will try another solution and here's my point for doing so:
- every now and then the comments rating would simply disappear;
- while looking at the hits to the server I sense some real performance impact to WP;
- plugin is somehow intrusive (did you really need to add that red bordered box on the plugins page?), using custom UI design (as opposed to available native WP backend UI) and way too many administration features at once.
If you can get this to work as expected and have the time to tweak the settings all the time, I would say - keep using it, there's nothing else around as powerful as this.
Thanks GD Star Rating.