Pros
If you live near it it's useful. The ability to move jobs, which improved during my time there, means you can change directions and try something else, There are some really good people working there and I am happy to have worked with them.
Cons
Appalling management and treatment of its employees. This is very much luck of the draw as to who you get. Those that are decent won't get on and you soon end up working for some self serving types. HR are utterly useless and generally don't care about the employees at all. They are not going to be interested in sorting anything out, not just my experience. Get a bad manager and you think talking to them might help. Processes and procedure so out of touch with what people have to do to make anything work. So much time is wasted on ridiculous things that should just work. Engineers are hugely undervalued, but not going though the latest round of redundancies, they can't get enough of them and I'm not surprised as I certainly wouldn't go back. Other supporting departments are still being culled though. If you are an engineer there are challenges there, but not technically, just trying to get the job done takes more effort than the complexities of a gas turbine.