The points mentioned are really good, but the chances of being scammed are very high right now because the projects right now are being started by many noobs who just try to scam other people. Manager’s background is very important for me because it is his reputation that is on the line.
I was once involved in a project; then after some time, it had to shut down saying that the central system had some so-called technical difficulties and wasn’t heard from them ever again. People lost their investments and were badly scammed.  Nowadays, this scamming has been increasing a lot.