Pros
Working specifically for The Lancet group of journals can be a good experience, especially given the passionate, smart, and hardworking people who populate the various roles that get the journals to press.
Cons
The editorial roles at The Lancet journals are underpaid given how well qualified and experienced staff are expected to be (and certainly underpaid compared with most high-profile competitors in London and elsewhere). Additionally, very poor management decisions often leave people in middling roles shouldering the majority of the work and unable to progress, with no ability to negotiate any increase in salary. Performance-related pay is an absolute joke, with a forced curve that leaves many of the hardest working people receiving annual real-terms pay cuts, with novelty targets valued much more highly than the actual work involved in maintaining quality output. Meanwhile self-confidence is valued much more highly than skill or experience in promotion and hiring decisions.