The latest NTFS-3G release never has know reliability problem. It's used by millions of users, appliances, devices, recovery medias, etc.
The most typical reliability problems are hardware or usage related. For instance disk, RAM, USB, cable problems, power outage, not properly unmount/detaching volumes, accidently overwriting or deleting files, etc. Or in other words, typically data loss is not file system related.
One notable exception is the Microsoft NTFS driver which regularly has serious reliability and data loss, corruption problem, for instance recently:
http://support.microsoft.com/kb/946676
http://support.microsoft.com/kb/950190
But thankfully they hired back one of their main NTFS architects not so long ago and surely their file system driver quality will improve too in the future:
http://blogs.zdnet.com/Bott/?p=473
Regards, Szaka