I've already registered my MEW address but...do I have to register again if I transfer additional EOS token from exchanges to my MEW?
no, you don't have to re-register. any tokens in a registered eth address at the time of the snapshot will be counted.
So I heard from different sources now that EOS will be ruling in 2018. Can anyone explain the technical advantages EOS will bring over the others? I would be happy if someone can explain a bit about that!
check out the link to eoscollective (few posts up). under "articles" there are a ton of detailed write-ups that address this question.