Backup software is hard and thankless. A sizable minority has bad ideas about how backup does/should work, and what their real needs are.
Backup software is an organization’s software-quality acid test. For Apple’s software spread, I would place it only after the file system and Core Data in the ranking of software that absolutely, positively must-work. It requires an engineering backbone of steel, sometimes even saying “no” to data-compromising requests from users, upper-management and marketing.