User blog comment:Kogath/Monster Hunter 4 Ultimate for the Nintendo 3DS/@comment-28303251-20151005051230/@comment-5569775-20151005123648

Defense is a bit less obvious than it seems, as you also get a Divine Blessing type effect with the defense boost, that stacks with the Armor Skill and Hi Defender(Food Buff).

Life really depends on the weapon and what attacks you do, as you heal based on the motion value of an attack; it also seems to have a 1/3 chance to proc and there's a cooldown of some sort for it. GS and Hammers can heal for a massive amount with their charged attacks, but because of the chance to proc, it's not guaranteed. I haven't tested with DB's but I assume they won't heal for much, due to low MV's, even if they do hit more frequently.

For GL's it depends on personal play style with them. Shelling type, doesn't matter in the long run as you can't heal off the fixed damage the shells do, or wyvern fire, but certain Shelling types might effect the way you play(like I tend to focus more on Shelling attacks with Normal and Long, but I focus more on non-shelling with Wide, so Wide might be my best bet if I were to use Life on a GL).

It's pretty good with SA, CB and IG, IMO; though I only have it on some of them. It's especially good with IG's that have Fleetflammer(Blunt) or Foliacath(Cutting), as they decrease the Kinsect charge time and the charge attack with the Kinsect has a rather high MV.