Pros
Frankly a great company to work for. The people are extremely smart, dedicated, and nice. Work is impactful especially when working with quants. Hours aren't particularly long and environment is laid back. Very diverse problems to solve and things to build, from high performance financial algorithms to web services. Great perks (free lunch, lots of holiday (30+ days), actual free cafe in office with professional barristas)
Cons
The culture of secrecy is still very much a thing, albeit not as bad as in previous years (or so I've heard). I have to leave all electronics in lockers when arriving at the office. Half of the company (quants, engineers, etc) is forced to work in the office full time with 3 days of WFH (but gets extra holiday), other half can WFH as much as they want but can also opt into working in the office full time to get the extra holiday. I'm happy to work in the office, but this is a con for people with families. Very much white male dominated, especially in engineering. GR badly needs more diversity.