Pros
I worked in books editorial. It was a pleasant working environment with a collaborative atmosphere and a good work/life balance. At a relatively low level, the pay seemed slightly above-average for editorial publishing jobs in the area. This meant the company was able to attract some really well-qualified, smart people so the colleagues were great. The mid-level management was really excellent - we had a very supportive, intelligent director who was assertive and commercially motivated yet also kind, considerate and always willing to advise where necessary (rare!). There was also a very strong union, which was very successful and had a positive impact on motivation, fairness and salary levels etc - yet was also very reasonable in terms of negotiating and working with top-level management.
Kontras
It's a shame there wasn't more career progression at the company - probably 95% of the people directly above me eventually left as the promotions they should have had were so slow in coming. These were all smart people with a lot of potential (which was obviously seen by the employers they left Informa for!) yet there wasn't really anything for them to progress to within the company. Also, employees were generally not pushed, challenged or trained - mostly just left to get very, very good at their current job - and consequently very, very bored with the lack of progression and development!