‘Aa’ishah (radhiAllaahu 'anha), relates that the Prophet (peace be upon him) said:

Verily the one who recites the Qur’an beautifully, smoothly, and precisely, they will be in the company of the noble and obedient angels. And as for the ones who recite with difficulty, stammering or stumbling through its verses, then they will have TWICE that reward.”

[Al-Bukhari and Muslim]