Most of the improvements come from Intel drivers including: full OpenGL 4.3 support and EXT_direct_state_access support. EXT_direct_state_access is so old and broken that it's no clear to me it's a good thing overall but there is certainly some conveniences having it.
More interesting, Intel added support to two new AMD extensions: AMD_vertex_shader_viewport_index and AMD_vertex_shader_layer. I'd love to see these extensions reaching ARB status and mobile.