The only one I turn on is HBAO+(Standard) and reflections - the latter is a mixed bag; looks nice in some places, odd in others (e.g. the rusted metal on the ground at Limsa Lominsa).
Parallax Occlusion implemented isn't particularly robust - e.g. on rocks which can have odd angled surfaces you sometimes get "ripples".
Water Tessellation ...
Was expecting,
https://www.youtube.com/watch?v=aAGmsJomTYM
got
http://i.imgur.com/FBXnsOa.png