They all look fine for the most part except for how they handle internal and external links. There the Wiki format wins out in terms of being intuitive and easy. It’s frankly the most important bit, and I think even HTML screwed that one up – a href="" is not intuitive, it’s possibly the most non-humane way I’ve ever seen for how to do links.
“I know, let’s make the tag to link to external sites the same one as we use to make internal anchor points. And while we’re at it, let’s use a totally opaque acronym to designate the link element. Because LINK would have been too straightforward.”