Avantages
The managers/directors really work hard to encourage modern tech culture of self-managed teams, fail-fast, engineers-make-the-engineering-decisions kind of organization. Most of the people I worked with were very transparent and genuine and encouraged you to speak your mind; not a lot of red tape or petty politics. Really invest in their engineers: 50 days a year to be used on whatever career development learning you want do. Even when they,ve had massive outages/bugs in production, I've never seen anyone blamed or fired for an well-intentioned mistake discovered in a post-mortem.
Inconvénients
Still an old company with some legacy artifacts. A few backend business functions still rely on IBM Mainframe, VB, SOAP requests etc. Only every now and then did I hear crap like "but we've done it this way for 10 years".