I've witnessed clemency healing for over 12K on a crit (look to reddit). Both are 1200 potencies and work a bit differently.

You can clemency far more often than equilibrium, infact you can do it back to back which is fantastic, and use it on someone else. It has a cast time as down side. Mana is pretty moot and just acts as a cool down since by the time you need to cast heals, flash spam is largely not relevant.

Equilibrium is instant cast which is its own benefit, and can be used in a pinch to heal yourself back up.

Between the two, I prefer clemency; more options in how to use it, and can be used twice along side paladins 30% convo is quite nice!