For some reason, I mis-read your original post, and thought Griss was your companion, I apologize.
The spirit breaker is a niche weapon, for clearing out the forbidden pit. Shadows take extra damage from holy, banishing, AND spirit. In most other areas, it will be outclassed by something else (like pally longsword vs undead)
For rogues and clerics, the leggings are more valueable, BUT ashen armor will replace it by end game.
For clerics, the value of the leggings does increase some, but they they get blessed plate too, a guaranteed drop from Duremas. For a non Agi-based cleric (likely), the hammer and leggings are probably roughly equal value. The answer would depend on what other equipment you had available, or intended on obtaining. (Eg, pally longsword is great, but difficult to obtain. Or perhaps you chanced a drop of Justice). For a player-based cleric, I think Maul of Terror would be a better choice for clearing forbidden pit.
Rogues can actually use the hammer, one of the few they can. But the leggings are much higher tier for rogues too. I think the adamantite shortsword in a rogue's hands would be more powerful than spirit breaker against shadows (due to damage multipliers on stab and flank), and if you are clearing the pit, you will likely do so late game. But, the breaker is also one of rogues best weapons against undead. It's a tossup for leggings vs hammer.
The Sonnet is also a high-tier weapon for me. It's extremely versatile, as few enemies have spirit res. It's kind of the reverse of the breaker in that it has no niche use, but is great a lot of places. The Breaker would be better against undead, for example. Icicle vs fire and orcs. It's very much a "set it and forget it" weapon. A jack of all trades, if you don't feel like carrying the armory with you, or switching gear all the time.
To cap this off, strength based builds will value spirit breaker less, and agi based builds will value it more. Its one of the best "light" weapons against undead, but stronger non-light 1H options exist. For a team that does NOT have a warrior, then trade the cleaver in for the leggings, every time. For ones that do have a warrior, you will need to decide what best suits your current setup.
Hope this helps, rather than confuses.
