To me, its best bits are;
1. AQL - I absolutely adore AQL- the query language that you use in Arangodb. I haven't seen anything like it so far and it was somethingI could pick up in 5 mins.
2. Multi-modal - love the idea of being able to use the same db for graph and object based data. With the new search and other geo features, this bit has become even more tempting.
3. Orchestration - ability to have self healing clusters of db nodes makes the overall backend super redundant and safe. and also helps with latency by enabling me to have a node in each region that I want to optimize for.
Despite all this, I almost always end up going for Postgres for my personal projects.
Coming to the negatives, for me the biggest missed opportunities are;
1. Not providing a free tier for the managed service. I really would want to use the service for small toy projects without worrying about a time limit. All of the managed service providers have a free/community tier and without it, I don't see their service succeeding.
2. Foxx server-in-db This one pains me so much. I feel Foxx is the killer feature thay have that can push them past Postgres. Having the web server and the db in the same node makes architecting the backend so simple. But Foxx really isn't designed with developer ergonomics in mind. Issues that i opened years ago are still open, without any major update which would make developing in Foxx less than a chore. I would drop other web frameworks+dbs in a heartbeat, if Foxx was easy to develop in.
3. No Jepsen report. No techempower entry for a Foxx+arangodb backend. No realworld backend app using arangodb. No major independent benchmarks.