Summary: I'm running two of these in a linux box (Scientific Linux 6) and am having absolutely no problems with them. They just run X, no games or anything and, yes, on the date I write this the 5830 is yesterday's tech. However, given the price of these versus a 6990, these give a little more GPGPU crank per dollar. I'm running OpenCL accessed via python (pyopencl). I switched from CUDA to openCL because openCL is, well, -open- and runs on more hardware.
Summary: If you plan ever to have more than one monitor, don't buy this card. Once you add the second monitor, you will experience flickering and tearing. ATI has not solved the problem after a couple years. I doubt they will any time soon.