Pros
Dynamic, live environment, good work-life balance, multinational teams of virtually every nation on Earth. Generally good business process and goals, good understanding of its business. Data-driven approach.
Cons
Software engineering in Booking.com is very clearly just a business tool, e.g. refactoring, testing, code reviews, proper software architecture are rare and not encouraged, the mantra is "being pragmatic and getting things done". You will not learn how to be a good software engineer here, except for trainee/junior positions. The codebase is a giant monolithic ball of Perl with all of its drawbacks. Technology is very conservative and often shortsighted. The company is hostile to non-iterative and breaking changes. Values of the company are good on the surface, but shortsighted, oversold and often have a lot of real life drawbacks (although effective enough to earn good money). The attitude "we don't care about what customers do not see" is steadily hurting the company from the inside, and huge network effect allows the company to sit on top of its huge hotel/user base.
