In my opinion Leda's greatswordis very good but you can get it only at the end.
Overall you only have three choices
1. Milady: If you want custom ash of war and raw damage.
2. Rellana's twinblades : Badass ash of war with dual properties. Deals fire and magic damage but less raw damage than Milady.
3. Leda Lightgreatsword is good for holy damage and has a very good ash of war that can target enemies from modrate distance.
Overall all three are good but depend on your prefrences.