This is an interesting article contrasting the two very different family law jurisdictions and how they compare.
Some key differences: Californians have no-fault divorce, child support is calculated very precisely by a piece of software and the division of property is far less generous to the financially weaker party: property acquired during the marriage is joint but other than that, you get out what you put in. Judges have far more discretion and needs play a greater role in England and Wales.
Overall I believe that Californian Judges adopt a far more formulaic, one-size-fits-all approach, whereas the English system, for all its faults, is a far fairer and more flexible system.
In keeping with their sunny dispositions, the Californians operate a 'no-fault' policy for the grounds for divorce. The primary basis for commencing a divorce in the state of California is 'irreconcilable differences', which is simply a box on a form that needs to be checked.The court does not take either party's behaviour into consideration in making its orders at any time during the divorce proceedings except, perhaps, for the purposes of child custody and, in limited circumstances only, legal fees.In contrast, England relies on a 'fault' system. One party must petition for divorce (or the dissolution of a civil partnership) and, in doing so, must prove there has been an irretrievable breakdown of the marriage evidenced by one of five facts: either adultery, unreasonable behaviour or certain periods of separation.