I'd get the 997S for sure, but if the choice was base 997 vs 996 40th, I'd take the 996.

The 40th edition 996 was the sportiest normally aspirated 911 except for the GT3. It was light, fast, had sport suspension, and a LSD. TO me, that's a much sportier set up than the base 997. There is a theoretical consideration that a special edition 911 with LSD might hold value better over the years (though 996's have suffered in this regard).