For a majority of these open-source benchmarks on Ubuntu 12.10 with the Linux 3.5 kernel, the AMD A10-5800K was competitive with the Intel Core i5 2400S "Sandy Bridge" processor. In some tests the A10-5800K was slightly faster and in other cases a little bit worse. For nearly all tests, the A10-5800K was fasted than the tested Core i3 "Sandy Bridge" CPUs.
There were also some workloads where none of the tested AMD APU/CPUs performed well, which may come down to AMD not investing as many resources as Intel when it comes to compiler tuning in GCC for new products. Fortunately, AMD is already working on Steamroller/bdver3 compiler optimizations for next year's products.
The AMD A10-5800K retails for $130 USD at the moment, which is a rather good value. The Intel Core i5 2400S meanwhile that was running against the A10-5800K in a number of the Linux tests is still retailing for $200 USD at the same Internet retailer (albeit the Core i5 3470 Ivy Bridge is also at the $200 mark).
On the plus side, the AMD A10-5800K with its Radeon HD 7660D integrated graphics are faster than Intel's graphics when using the Catalyst Linux driver. The Radeon HD 7660D graphics really aren't that bad and work well with Catalyst. Unfortunately, when attempting to use the open-source Radeon Linux driver on the A10-5800K, things didn't work out too well; when Trinity works well on the open-source driver in the tested configuration, new benchmarks will come. It will be interesting to see how the HD 7660D graphics compare to Intel's Ivy Bridge graphics on their well-supported open-source driver.
If your main concern when it comes to graphics support is the vendor backing open-source Linux drivers, Intel is the definite winner. Intel's only Linux graphics driver is open-source compared to AMD officially supporting the Catalyst proprietary driver on Linux and then the semi-official open-source driver but that driver is not nearly in as good shape as Catalyst. The open-source Radeon Linux driver still doesn't have proper power management support, the OpenGL support is still at GL 3.0 even for the latest GL4-capable hardware, the performance is well behind Catalyst, features like CrossFire and advanced AA modes are non-existent, and the Radeon HD 7000 series graphics cards still don't have proper end-user support.
All-in-all if you are looking for a sub-$150 USD processor for a Linux system and don't mind using the Catalyst graphics driver and aren't strictly using workloads where AMD processors don't tend to do as well (the aforementioned scientific tests shown in this article on GCC 4.7), the AMD A10-5800K is a very interesting product. Coming up next week will be more AMD Trinity/Piledriver benchmarks under Linux that will share the performance-per-Watt data, results on compiler tuning/optimization work, benchmarking binaries generated by different compilers targeting "bdver2", and other interesting metrics.