Php 7 opcache v php 5.6 xcache

We're provisioning a new server and are deciding between (php7 / opcache) and (php5.6 / xcache).

We run a few chunky ecommerce sites and want the best possible performance.

I'm looking for comparative results between the two, but cant find any anywhere.

Does anyone have experience in the two side by side?

In terms of comparative results, Zend Opcache was already better than xcache since php 5.5.

Find a coparison here: http://massivescale.blogspot.ro/2013/06/php-55-zend-optimiser-opcache-vs-xcache.html but you have the graphs below in case reference goes away in time.

So conclusion is: the (slightly) better choice is opcache since php 5.5, and if you add the fact that php 7.x is faster in itself, php 7 + opcache is the way to go without any doubt.

Graphs: