ArrangoCD
When we decided to go over to fully decleared cluster instead of using KubeApps, we considered Arrangocd vs. Flux. We wanted a primarily automated system, with Git being the primary tool to handle cluster state. We already had experience using Flux in other projects and had completed a symbiotic setup of other tools with Flux's image automation, alerts and recievers to automate releases, version management and more. That in addition to it being possible to run Arrangocd and Flux side-by-side made us choose Flux for our cluster.