KDMARC is a useful diagnosis tool in an email deliverability arsenal. Anyone serious on that matter should at least try it and see how it complements its other tools.

The tool itself is very useful to diagnose your authentication issues and confirm your DMARC is properly aligned. A lot of efforts were put into making your authentication checks and implementation easier with all the records checkers, record generators and the smart control feature. Their support is generally fast (24h or less) and friendly. The dev team was quite fast to squash the bugs happening along the way.

There is margin for improvements though. Right now, it's still a tool for e-mail deliverability geeks. I feel like it could be so much more beginner friendly in the way reports are presented and labeled. Cost can be prohibitive if you have many domains to keep in check on a regular basis... or want to take advantage of the smart SPF feature, to get rid of the 10 DNS lookup limit for instance.