DataStores are very reliable if you take out the factor of unpredictable failures which seem to be more common nowadays. Other than service disruptions, regular DataStores are very reliable.
There are a lot of discussions and such about the reliability or unreliability of DataStores, but it’s within my belief that they aren’t unreliable. If Roblox follows through with the updates they promised at RDC, then they will have an even higher degree of reliability and even more utility for developers.
Ultimately if you heard this discussion from DS2, then it solves a nonexistent problem. There are plans to natively support what it can do (backups) and presumably better than a Roblox library can. You’re better off using libraries that don’t completely baby you through the process and allow you to extend properly upon the service to resolve real issues, such as ProfileService and session locking (an especially important consideration when systems like trading exist in your game).
You’ll want to do as much as you can with your own libraries and be mindful of the limitations imposed upon their usage. If you work under those limits, you should be gold.