All the following paragraphs are copied from http://www.openstack.org/software/grizzly/
So I recommend you to read it there, but for your convenience they are quoted below.
Note: a short video is available here
OpenStack Grizzly, the seventh release of the open source software for building public, private, and hybrid clouds, has more than 230 new features to support production operations at scale and greater integration with enterprise technologies. The OpenStack community continues to attract the best developers and experts in their disciplines with more than 517 contributors making 7,620 updates in the Grizzly release.
New Features in Grizzly
Compute delivers improved production operations at greater scale, with “Cells” to manage distributed clusters and the “NoDB” host architecture to reduce reliance on a central database. Improvements in virtualization management deliver new features and greater support for multiple hypervisors, including ESX, KVM, Xen, and Hyper-V. Additional functionality was added for bare metal provisioning, shared storage protocols and online networking features such as the ability to hot add/remove network devices.
OpenStack Object Storage
Cloud operators can now take advantage of quotas to automatically control the growth of their object storage environments. Additionally, the ability to perform bulk operations makes it easier to deploy and manage large clusters and provides an improved experience for end users. Cross-origin resource sharing (CORS) enables browser connections directly to the back-end storage environment, improving the performance and scalability of web-integrated object storage clusters.
OpenStack Block Storage
The second full release of OpenStack Block Storage delivers a full storage service for managing heterogeneous storage environments from a centralized access point. A new intelligent scheduler allows cloud end users to allocate storage based on the workload, whether they are looking for performance, efficiency, or cost effectiveness. The community also added drivers for a diverse selection of backend storage devices, including Ceph/RBD, Coraid, EMC, Hewlett-Packard, Huawei, IBM, NetApp, Red Hat/Gluster, SolidFire, and Zadara.
The leading network-as-a-service platform enables advanced network automation, allowing users to control their networking technology of choice. Those choices grew tremendously with the Grizzly release, with the addition of support for Big Switch, Hyper-V, PlumGrid, Brocade and Midonet to complement the existing support for Open vSwitch, Cisco UCS/Nexus, Linux Bridge, Nicira, Ryu OpenFlow, and NEC OpenFlow. OpenStack Networking achieves greater scale and higher availability by distributing L3/L4 and dynamic host configuration protocol (DHCP) services across multiple servers. A new load-balancing-as-a-service (LBaaS) framework and API lays the groundwork for further innovation from the broad base of networking companies already integrating with OpenStack.
OpenStack Dashboard brings an improved user experience, greater multilingual support, and exposes new features across OpenStack clouds, like Networking and LBaaS. The Grizzly Dashboard is also backwards compatible with the Folsom release, allowing users to take advantage of additional features in their Folsom cloud prior to a full upgrade to the latest version.
A new token format based on standard PKI functionality provides major performance improvements and allows offline token authentication by clients without requiring additional Identity service calls. OpenStack Identity also delivers more organized management of multi-tenant environments with support for groups, impersonation, role-based access controls (RBAC), and greater capability to delegate administrative tasks.
OpenStack Image Service
There were major advancements in image sharing between cloud end users, and the creation of a set of common properties on images to provide more discoverable images and better performance when retrieving images.