They failed every single Jepsen test, including the last one [0]
granted, the failures were pretty minor, especially compared to previous reports (like the first one [1], that was a fun read), but they still had bad defaults back then (and maybe still do)
I would not trust anything MongoDB says without independent confirmation
Reputation matters. If someone comes to market with a shoddy product or missing features/slideware then it's a self created problem that people don't check the product release logs every week for the next few years waiting for them rectifying it. And even once there is an announcement people are perfectly entitled to have scepticism that it isn't a smoke and mirrors feature and not spend hours doing their own due diligence. Again self created problem.