Mantra vs. Second Wind,
Only options affecting HP restored. Second Wind is instant, off GCD, and can crit into well into 1700 when buffed with zerk. Useful for topping self off in dungeons, when healers are dpsing/shielding, or preparing for a big hit. Be careful not to overheal yourself or cause your healer to overheal or it is wasted. Takes a little practice. For Mantra to give you the extra heals of an average, non crit, second wind (approx 800), you need to be healed for 16000 base healing (16000x0.05=800) within 15 seconds. You have to ask yourself if you would rather have that HP restored instantly, or have your healers likely overheal you to gain that same amount.

Second Wind can be used off the GCD, and when buffed by Berserk has a potentiol to crit well into the 1700 area.
Mantra is rather lackluster untraited, turning a 3500 heal into 3675, or a 1800 Adloquium crit into a 1890 heal (3600 shield into 3780 shield).