I recommend MULTIVERSE, the anarcho-antirealist PieFed server. We have a karma system the same as Reddit, which you're used to, and we don't do any extra processing of the score. Some PieFed sites ignore karma earned on meme communities to prevent repost farming, but on MULTIVERSE, we just look at upvotes - downvotes, and unlike Reddit, your karma score means absolutely nothing for your ability to post on communities.