I'd pretty much echo AA's comments.
On the Sauer, the "Model 8" may or may not be the correct designation, but I'm guessing it means the gun is a fairly plain boxlock extractor. If it has a straight grip, it's more likely to be a prewar gun. All the post-war West German Sauers were pistol grip guns. But you can look for a date code--3 or 4 number month/year designation--on the barrel flats, plus maybe just "Germany" as opposed to DDR or GDR.
If both are in equal condition, the prices ought to be about the same--which it looks like they are. If I were you, I'd consider personal preference and whichever of the two is in better condition as the deciding factor. You might also want to check the amount of drop in the Sauer stock. Athough Sauers don't have the extreme drop you often find in older American guns, you may very well find that the Bernie is stocked higher and fits you better. That's another key consideration.