1. Nothing about ethos, but a lot about an attractive return on your investment
This covers 90% of all Blockchain Projects Scams. There were so many proof of stake coins with 10 000% ROI in just a few weeks, but who would buy this coins?
5. Negative reviews on various Internet platforms
I would be careful with this one. EVERY coin and project has negative reviews on some sites. Search for Bitcoin Scam for example