I used different DMARC tools over the years. I used a trial account first for 14 days and then decided to purchase codes from Appsumo.

I like that in KDMARC I can control DMARC and SPF records right in the KDMARC app.
(Basically they are using a CNAME and TXT record pointing to their system. Once setup, you can manipulate those entries directly in KDMARC).
This allows for much easier management of those records.
Great buy IMHO.