Magento 2.0 is here!
Speed in General
From our testing, Magento 2.0 is significantly faster on the frontend and on the backend.
Full Page Caching
With the new Magento 2.0 system, full page caching will now be available on both Magento 2.0 Community and Magento Enterprise 2.0. Pages with many database calls will have them all built into a single page that will be rendered ahead of time into HTML, which will reduce page load time and server loads significantly.
Magento 2.0 is also compatible with Varnish 4, which will also help with load times.
Rather than one mySQL database, Magento 2.0 will include the ability to have an additional database for orders, which will be able to operate at an optimal level without the load of the traffic from the site in general.
Magento 2.0 Security
Upgrading to Magento 2.0 for the security updates is an excellent idea. Magento has been hard at work to improve Magento 2.0 security; for instance, Magento has been completing a wide variety of security testing with external partners and the Magento community as a whole to help analyze and uncover issues. https://magento.com/security/news/join-magento-2-security-challenge