I’m keeping a close eye (or as much as I can anyway) on PHP7 and what it means for the future of the language. Installing in your local dev machine is risky, especially if you have ongoing work. As usual, Vagrant comes to the rescue!
Rasmus Lerdorf has put together a Vagrant box to ease in the setup and isolate your testing.
If you use Atlas, check out the box here. Otherwise, the readme is available on Github