Pros
Good people to work around if you're in the right department, some benefits with a good canteen. Usually a strong stable job to keep for many years (although not so much recently with covid related redundancies). Can be a great place to learn and develop with schemes for people early in their careers. Some positions have flexi time which is great. Good pension scheme if you're looking for that
Cons
An old site and whole site could do with being brought up to date with a revamp, some areas in need more than others that just by with 50 year old equipment "if it ain't broke" mindset so funds don't seem to get allocated to these areas. Seems newer areas are fine to work in. Can be at risk of being stuck in the same position without much of a pay increase or clear progression path depending on manager and team. Can be quite competitive for positions. If you don't cycle from the nearest station (which is a bit ot a way) or drive, it can be quite hard to commute to site. Clear divisions between each department and areas rather than a sense of working together for the same company