I've had the pleasure to build a small website with Kirby and it was such a joy to use as a developer. The only problem I faced was with my client as he was used to Wordpress and making the transition to Kirby was a bit rough for him.
I'm lightly looking into alternatives to WordPress. Obviously CraftCMS come up, but being a paid product - nothing work with that per se - does limit its appeal for some projects / client. So maybe there's a place for Kirby?