In my previous job at VMware I've found code reviews to be very useful. Apart from finding bugs at early stage as pointed by this article:

- Code reviews are an effective means of knowledge transfer among engineers.

- It makes engineer more conscious while writing code since the patch will be read by others and hence less likely to cut corners/put hacks.

- Since the patch should be understood by others, author needs to ensure the code and the change/commit description are well documented.

- It lets your co-workers/manager know about the amount of progress made on a task.