In most of the x11perf benchmarks, SNA is also able to boost the performance over the stock 2D acceleration paths.
Overall, Sandy Bridge New Acceleration (SNA) is looking up. It is still not fully baked (JXRenderMark this time around causes issues and at various points in the past there's been rendering problems and stability issues), but when it works, it tends to work damn well. It works for Ironlake and previous-generation hardware too, but that is also where the support at times is less than stellar.
SNA is not enabled by default at this time but requires building the xf86-video-intel DDX driver from source with the "--enable-sna" switch. It is not known if or when Intel will enable it by default. There is also the Glamor acceleration to think about as well, which is our next test target.