Pros
Fun, social, highly educated, young staff. Great office location in Notting Hill. Most teams have semi-regular travel opportunities that are rare especially for grad/early career jobs. Serious drinking culture. Great starter job in that it's incredibly marketable when you look for your next job (pretty easy to get interviews) and you can learn a lot, quickly. If you are intrinsically motivated and able to navigate opaque office politics, there are possibilities to do good work and make good contacts.
Cons
Travel opportunities and supposed flexibility used as excuses for shockingly poor pay and oddly negative, almost confused management style. Communication is all over the place. Flexibility for employees' schedules allotted seemingly arbitrarily. Much of management is aggressively hands off, and impressively complacent. There are many exceptions to this of course, but the structure they work within makes their good intentions look like an absolute grind, and I really don't envy them for it at all. I also don't blame them for giving up eventually. This also removes any motivation to stick around for any advancement opportunities available within the company. HR is better than in the past, but others' exit interview content was leaked several times during my time there - I don't even think you can blame the youth of the company employees for this level of unprofessionalism. Two month notice period also complicates moving on to next role. Company solidly founded in old boys club culture. While the numbers m/f are pretty equal in management, the culture prevails structurally despite the predominantly liberal political culture. I'd love to see a full gender pay spread, because significant anecdotal evidence suggests it could be embarrassing for them. I hope I'm wrong. Everyone I keep in touch with who left the company said the culture damaged either their motivation, self-confidence, and/or overall happiness levels in some way. On this point alone I would say the positives of the job might not end up being worth it.