Pros
Good science, focusing on immuno-oncology and specifically bispecific antibodies means most of the scientists are immunologists. People are generally friendly and they have (had, before covid) a fairly social group organising events etc. Science can sometimes be overridden by political or business decisions, but not more than at other companies. Various perks such as yearly bonuses, bupa coverage, healthshield etc sweeten the deal.
Cons
They have a "consensus-driven culture" and "conversations about science" are strongly encouraged and practised. In practice, that means a lot of never-ending back-and-forth discussions and meetings, walking back on previous decisions (even when there is no new data to warrant that), a great deal of speculation about what might or should be rather than just wait for the results of the experiments. Sometimes unrealistic decisions are made, such as to progress two INDs to submission at the same time with only 80 employees, then wonder why things don't go to plan. The recent financial difficulties seem to have been solved by the recent merger with Spring Bank, but it's not clear how long that money will last.