How does working in London differ from Menlo Park? (In terms of career growth/promos, what kind of teams are available, what kind of projects you get to work on, etc) Is it easier to get promoted faster in MPK than London? Anything specific for the Production Engineer role? I know about the comp and weather differences between the two cities. This question is for things specific to FB.
London office sucks for PE role big time. There are only a couple of projects available for PE and managers are dicks. Don't go there, you will regret that. Dublin or MPK are much better choices for PE.
One thing to consider is a lot of London people often stay very late (like 8pm) to accommodate for Menlo Park
You can come in later if you're expecting to stay late. Promotion will always be better at the HQ.