Pligg engine stands behind of many "public voting" - social web 2.0 sites. Most prominent is digg.com (is not pligg based i guess). Today I tried out the pligg 9.8.2 beta engine, which is the current released version at the moment.
I'm impressed about pligg functions, and configuration possibilities, so i think i can use pligg in my future project. But I'm not impressed with the quality of the current version. Of course it's beta version, but we know other kind of betas (e.g. google applications) that do not breaks on every second click. And if you decide to install some additional plug-ins on this version, be aware, it can make, the situation only worthiest.
Unfortunately I can't use this version productively. I hope that pligg people will soon fix existing bugs in next betas, or even they will makes us happy with very stable version 1.0.
By the way, does anybody know when pligg version 1.o is planed to be released? I read somewhere just meaningless "hopefully soon".
P.S. The default template of pligg looks bad too, but that is another story.