Simplify the following text for a Grade 11 native English-speaking person.
Original: Signed by Simon Cowell , they enjoyed fair success worldwide , but particularly in the UK , parts of Europe , Russia , parts of Asia , Brazil , Israel , Australia , New Zealand and USA .
Simplified: Signed by Simon Cowell , they enjoyed great success worldwide , particularly in the UK , most of Europe and Asia , Russia , Brazil , Australia , New Zealand and the USA .