After the deep investigation I confirm that MONERO is the best privacy currency. So I strongly recommend MONERO for all people who need extra privacy.
Monero is bullshit. Dash is also bullshit. They are effectively scamcoins in a sense that they boast about having privacy while in reality they have weak privacy. They should not be advertised as good for privacy because their privacy is directly derived from the assumption that they are massively adopted and the most dominant crypto out there. Here's a reality check. Are they massively adopted and most dominant cryptos? No they are not. Hence, their privacy, which depends on their adoption, is badly lacking. They are not anonymous. So please, stop spreading misinformation.
I also want to underline this often overlooked, but crucial aspect here:
If I would invest in a cryptocurrency, then there is the technology on the one hand, but on the other hand, a big factor is adoption and market coverage.
Think of how long it took for bitcoin to gain enough public attention for a significant global adoption to follow. Now, bitcoin has proven to be a technology that is capable of handling value transfer in a safe manner. We should keep this momentum and continue it, and do not split up in thousands of other currencies, because that will cause uncertainty and an overall disinterest in cryptocurrencies.
Another point is daily use:
If I have to go through the hassles of converting to another crypto (Monero, whatever) and converting back to bitcoin, just because the bank account exchange service only pays out bitcoins and the online shop where I want to buy something also accepts only bitcoins, then it's just too cumbersome to be done by a typical user (not talking about the fees that have to be payed for each conversion to another currency).
Bitcoin Mixers are just a super awesome hassle-free way of a bitcoin in -> bitcoin out transaction that are ready for productive, fast and easy use. Combined with a bit of understanding of the blockchain technology, perfect privacy is possible.