Macrium Reflect is the most respected disk imaging tool on Windows. It does one thing exceptionally well: take a byte-level image of a disk (or partition) and let you restore it to identical or different hardware. IT professionals have been using it for over 15 years.
BackupKit doesn't do disk imaging. It does file-level backups to cloud or remote storage, on a schedule, encrypted. Two different problems, two different tools.
The interesting question isn't “which one is better” — it's “do you need both?”