Whonix is superior to Tails because Tor runs in a separate virtual machine (the Gateway) from the main operating system (the Workstation), so an attacker has to find an exploit to break out of the Workstation VM to bypass Tor and determine your real IP address. On Tails, an attacker has to find a privilege escalation exploit to gain administrator privileges. Privilege escalation bugs for Linux are more common than VM escape bugs for VirtualBox. If you read through security announcements, you'll see multiple privilege escalation bugs over the last few years, but I haven't heard of any bugs that allow someone to escape a VirtualBox VM. Both are far more secure than running TBB on Windows or even a regular Linux distribution. The only thing more secure than Whonix is running Tor on a physically separate computer than sits between your main computer and the internet, which we call an anonymizing middle box. Also, you can configure the Whonix Gateway to use bridges just like with Tails. Whonix is a pair of VM images that you import into an application called VirtualBox, which runs on Windows, OS X, and Linux. So you can get better security than Tails without leaving your favorite operating system for non-Tor things. Best of all, you don't have to reboot to switch between the two activities. You could "pad" Tails by running it as the Workstation VM and routing its connections through the Gateway VM but I wouldn't recommend it, because you run into the "Tor over Tor" problem, where one Tor doesn't know what the other is doing, and you might end up with the same relay for your entry guard and exit node, which would kill your anonymity.