Good for:
Choice and price for consumers
The aircraft manufacturers, who have full order books
The airports, who are growing all the time
The industry, in that competition creates innovation and progress
The vastly increased number of people employed in the industry
Bad for:
Legacy carriers with high cost-base and complacent management
Employees who think they are 'worth' more than the market will pay
Unsuccessful entrepreneurs/investors who are trying to ride the trend, but will fail
Politicians who liked to control the industry through flag carriers
No effect on:
Safety