Really pleased with the new version. The NET button on the ladder is very convenient when bets are partially matched and you're going for free bets. Setting and retaining your balance in training mode (provided you green up each time) is another plus.
A word of warning about training mode; it's useful for testing new strategies and automation but don't use it exclusively without placing occasional real bets. Many users (usually people new to trading) have had their accounts restricted by Betfair for excessive use of Betfair's API without generating any commission.