Which weapon do you often choose to improve with the Chalice? Here is the effect on damage for the most common weapons.
Longsword
Before: 1d8, average 4.5
After: 2d6, average 7 (+55%)
Greatsword
Before: 2d6, average 7
After: 3d6, average 10.5 (+50%)
Bastard Sword
Before: 1d10, average 5.5
After: 2d8, average 9 (+63%)