SoB or SoC?Follow

SoB is better to PvE with, because it's steady and consistent damage and studies have shown that overall it does more damage, and it hurts you in the process so you wil need to get healed in groups which will help your mana regen.

SoC is better to PvP with because you don't need extra sources damaging you and it is bursty in nature. In PvP burstiness wins fights.

If you're solo grinding, I would still recommend Seal of Command. Maybe I've just had bad luck with adds, but I can't ever seem to fight less than 3 mobs at a time. Also, judgement of blood(when it crits) can shave 300-400 life from your health bar(not much, but if you're like me and are taking damage from multiple enemies, you don't really want that to happen)

For instances and such when someone else is tanking(lolret amirite?) blood will really help you out.

I've found some use for seal of blood in group pvp(battlegrounds, I wouldn't dare use it in arena) when an enemy is at less than half HP and you're fairly certain the consistent added damage from blood can get the job done.