I've come across silver swords with better stats than Aerondight as well but chose to use Aerondight because the stats level up. When I got Aerondight, it caused a maximum of, I think, 615 damage points. Now it causes a maximum of 725, and since I'm not through with my NG+, I guess that the stats will level up even further. So far, it's the best silver sword I ever had. It does, however, need a lot of repairing.