Arango is doing so much right now--their SaaS version "Oasis" coming out this year, SmartJoins for faster multi-cluster joins and now ML.
I admit I liked Mongo for it's document storage. But I didn't like Postgres due to my irrational dislike of SQL Then I challenged myself to try out a graph database.
ArangoDB presents things like Mongo (as documents), has a much nicer query language than SQL (or just use GaphQL) and does graph stuff; all while being amongst the top 3 or so in benchmarks that are designed to test only specific types of databases. If databases did triathlons, ArangoDB would be unbeatable.
Only two issues that I struggled with are/were Kubernetes cluster stuff, like sharding, but this is common to cluster DBs I think.