DS3 has solid capacitors that are supposed to last longer (though I doubt an S3 will die before you're ready to build a new system anyways), and I *think* it also has RAID support, as well as the ability to handle the new 1333 quads.
In any event, if you're not gonna be doing hardcore things, just get the S3. It's the same for OC'ing, etc and it's a winner of a mobo.