The only unrar on the Mac you will ever need.
Yuki's Fast UnRarrr does one thing only and it does it extremely fast and efficiently: It extracts RAR archives. Whether they were created on a Mac, a Windows or a Linux box. Encrypted or not. Split into multiple volumes or single files. Large or small. Blue or pink.
You can buy this handy tool in the Mac App Store for 99¢. Ridiculous, but true.