Pros
Talented and lovely people and a very positive atmosphere. HubSpot Berlin is now big enough to be a "serious" employer, with all the stability and some of the perks and amenities you would expect from a large IT employer. At the same time, it is still a dynamic and fast-moving place with lots of cross-functional opportunities and steep expected career trajectories in most roles.
Cons
Right now there is no Human Resources team in Berlin, causing inefficiencies (having to translate and explain German laws and conventions to Dublin-based folks). This situation should improve very soon though as far as I know. There is no engineering team in Berlin yet, so fewer technical roles and opportunities to liaise with developer teams than in other offices.