After encountering some issues configuring and running Metasploit framework on BackTrack 5 R3 in a virtual machine, I have decided to finally make the switch to Kali.
So far, the decision was good. Kali runs fine both in virtual machine and as a live USB stick. The interface is nice and sleek if not a bit too dark and lacking any colors. But it's customizable so it's not a real issue.
I also like the new "Start" menu and how applications are arranged. It's easier to navigate than BackTrack.
The Top 10 Security tools is also a nice addition and lists the best tools you can use like the Metasploit framework for all your exploitation needs, Aircrack-ng for testing and penetrating wireless networks, Wireshark for analyzing network traffic, Nmap for discovering targets and their weak spots and some others just as useful.
Everything runs good without unexpected errors or other anomalies. Instalation is very straightforward, has an intuitive GUI and provides all sorts of neat options (like encrypting the drive).
You can get Kali and read more about it here.