Pros
Really friendly people, overall has a family feel. Few official social events but many impromptu ones. You also get the chance to travel to their big annual conference - although you work your behind off (14 hours days) when you're there! Opportunties for progression career development in some teams.
Cons
Teams are siloed and unrealistic long-term ambitions mean everyone is massively overworked. Money is spent on more senior staff (often the MD's friends/former colleagues) rather than adding personnel that actually do the work. Teams that lose people are left to flounder on until HR evenutally get round to doing anything. Ideas are smothered and too many "characters" are allowed to carry on with disrespectful, lazy, spiteful behaviours.