You are compensated both with credits and priority points for doing QA reviews.
You earn priority points the same way as for CQR reviews.
The amount of credits you earn in general depends on the project’s word count and the number of mistakes you reported.
Be aware that the credits earned for QA jobs will be added as bonus credits. This means that the credits will become earned 30 days after you post the review. During this period, the credits will remain pending.