By using PHP 7 we have found that page load times in Moodle improve by around 30%.
~~At MooPi we compile PHP 7 for armhf from the sources available at dotdeb.org (Dotdeb only provide native i386 and amd64 packages).~~
To save you the hassle of compiling these yourself (it takes ~6 hours) we host a public apt repository of the armhf compiled .debs. This is a Howto guide to using them.
Please note, I can take no responsibility for the quality of these packages.