The K7S5A Pro has USB 2.0 and higher memory performance. If they carried over the onboard audio that came with my revision-1 K7S5A, then it's at the opposite end of the spectrum from the A7N266-VM's nVidia Soundstorm-certified 5.1 digital + analog audio, however.
The A7N266-VM has onboard GeForce2MX-level video, not suitable for advanced 3D gaming but good for general use (a bit fuzzy at high resolutions though).
The A7N266-VM is a very reliable board, we now have about 25 of them at work, and there seem to be very few Forum users having problems with them.