Pros
Good benefits and pay Some talented people Decent technological edginess
Cons
You work with internal frameworks which are badly documented and bring questionable value, just check the 'open source' version of Cougar on github (the documentation is a joke). I didn't like the atmosphere in the office, I felt a lot of power struggle between the managers, constant team reassignment, lack of team spirit. The security concerns can put undesirable pressure on the implementation decisions. Low autonomy as a developer (very difficult to introduce new technologies/practices different then the 'Betfair way') . Basically a top-down culture where architects and managers decide everything. Lack of connection with the business for a developer - you just get a bunch of requirements with no explanation regarding how they bring value to the business or what are the long term plans