Pros
Great work life balance and inspiring to work in a scientific field which is doing some cutting edge work. Nice friendly staff who do what they can to make the environment very enjoyable to work in. Good to use as a stepping stone to another role (see comments in cons section on reasons).
Cons
Critical parts of the business are underfunded and under supported which can lead to poor job satisfaction if you happen to work in that area. Generally poor payers of salary however work life balance compensates for this if you can afford the luxury of living in London on a below average salary or are just building experience for the next role. Lack of diversity in senior management and opportunities for career progression and promotions - seems to be a lot of talk to address this but no action. High turnover of staff.