"S" or "A" they're both basic cameras. Read the reviews at what is accepted as the best review site of all click here. The main difference between the two is, the S80 is wider at the wide end, and shorter at the long end.
Sorry John, The S80 has a 28-100mm zoom lens whereas the A620 lens is 35-140mm. The result being the 620 has a more powerful zoom (will get you closer into the action), but if you're into shooting landscape or groups of people indoors the 28mm of the S80 would be more benificial. I think my preference would be the A620.