We are biased. BackBox Linux is our favourite Linux Pentesting Distro, and we have blogged extensively on this distro with some great user comments.
The distro just works well and works fast. BackBox is an Ubuntu-based distribution developed to perform penetration tests and security assessments. It is designed to be fast and easy to use. It provides a minimal yet complete desktop environment, thanks to its own software repositories, which are always updated to the latest stable versions of the most often used and best-known ethical hacking tools.
The community is particulary helpful and we would highly recommend that you check out this distro.