For me the number one best feature has always been the TP Article system because it gives you the ability to add as many extra pages as you like and the type of content can be so diverse.
Next would be the blocks and panels and here again the attraction is the wide ranging type of content.
After that comes the Frontpage option(s) and then everything else on the list... I voted for all, of course.
As for folks showing up and voting, I've always held the opinion that aside from our forum staff we've never had really high numbers of active members when compared to the numbers of downloads of TinyPortal. As tino said, people don't tend to show up until they have an issue that they are unable to resolve on their own.
I think that maybe they are just busy with their own forums/site and don't visit here unless they need us to fix something.