Is OneCoin a scam?

Could you please elaborate on the legitimacy of OneCoin? There seems to be a lot of buzz surrounding this cryptocurrency, but I'm unsure whether it's a genuine investment opportunity or merely a fraudulent scheme. What are the red flags that indicate a potential scam? How does OneCoin compare to other well-established cryptocurrencies in terms of technology, regulation, and transparency? Are there any reliable testimonies or evidence that support or refute its credibility? Your insights would be greatly appreciated as I'm considering investing in it but want to make a well-informed decision.