The reason why I left negative feedback is because they are intentionally misleading people by spreading misinformation about CoinJoin/Wasabi, likely to attract more customers to use their centralized mixer.
I would never give negative feedback for someone giving their opinion but what they are doing is intentional and untrustworthy imo.
Furthermore, I did some research after leaving the feedback and I found more dodgy things. You already linked to the Wasabi vs Bestmixer topic but they appear to be tainting other people's coins with dust attacks.
Here is a quote from their website why there is no information about their staff or company:
In case that is what you're expecting, and if you're disheartened to find that there is no such information for BestMixer.io, please keep the following in mind: In order to continue providing you with the greatest amount of anonymity available in the cryptocurrency space, we need to preserve our anonymity as well...................And, most importantly, since our service is completely anonymous and we are answerable to no one but the client whom we serve, we will do whatever is necessary to keep the confidentiality of every transaction regardless of where in the world they originate from or what the government policies in those countries may be.
So in short: they are fully anonymous, they don't store your data, they aren't registered under any jurisdiction and they answer to nobody.
Now read section 4 and 8 from their ToS:
https://bestmixer.io/en/termsSomething is really off about them.