It all depends on how you approach it. Different coins have different opinions on how anonymity should be implemented.
There is in my opinion not something as 'this is the most anonymous' coin. Clearly the fact that we are talking about 'more' or 'less' anonymous is that all of them have positive points and flaws. Else we would answer this question with: "they are all 100% anonymous, just pick the flavour which you like most". For a comparison, someone has recently put some work in that:
https://bitcointalk.org/index.php?topic=2669844.msg27619280#msg27619280They are missing some of course.. e.g. anoncoin which is there from the start but is often overlooked since they care mainly about the tech and algorithm and not about marketing and pumping the coin. In a conversation with them when I ask how they are different they actually were quite open to how other coins approach the problem instead of answering: "we are the best", which is how it should be... they should not compete, they all want to achieve a common goal and are learning (and sometimes stealing) from each other.