The reason your question is not a good question is because of a few different reasons:
The answers about what is the best CMS will change, which makes it too localized:
This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, see the FAQ.
In other words, Stack Overflow posts should be useful to future visitors, and if the best CMS system changes, the post will then contain inaccurate information. As a result, "recommendation" questions are closed here. This doesn't mean they're bad questions, they're just not good questions for Stack Overflow.
Answers as to the best CMS are not constructive
In addition, the question is also not constructive because it's impossible to answer this with facts and references. In short, the answers will most likely be the author's opinion.
As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or specific expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, see the FAQ for guidance.
Again, this doesn't mean it's a bad question, and you can most likely find that it's been asked and answered elsewhere on the Internet. If not you can use Google Trends to compare different CMS's and find the ones that are searched for the most. This may not mean it's the best, but it can mean it's the most popular, which again has no basis in facts.
Questions asking for lists of things, or polls, are not constructive
In your question, you are basically asking for a list of things, which tends to attract a lot of spam, and is also plagued with the localization problem. What's hot today won't be tomorrow.
Hope this helps! For more information and guidance, please see Real Questions Have Answers. Good luck in your search for a good CMS!