On his site Carlos Buenosvinos has a new post talking about the experience they had at @AtrapaloEng with PHP 7 and shares some of the improvements they've already seen so far.

On Monday, Badoo blogged about its migration to PHP7 (https://techblog.badoo.com/blog/2016/03/14/how-badoo-saved-one-million-dollars-switching-to-php7/). Those are great results! At @AtrapaloEng, we’re running already tests in production to perform the same step. We could have started some months before, but we’ve been struggling with the php-msgpack extension and its (un)support for PHP7. We hope to deploy PHP7 in all our server during this week but we would like to share with you what we have seen so far.

They share some graphs showing the changes when PHP 7 was deployed on their systems for both memory consumption and overall load average. They also talk about the boost in performance as far as response times and, an often not reported statistic, how it sped up their unit test runs too.