Lesser Absorption

The internal mechanics of this enchant are that it has a 5% chance on you being hit to put up an invisible shield that absorbs 25 damage. Basically a weak, invisible PW:S. I have yet to see an absorb message on the first hit from a mob, so I would assume the shield gets put up after you get hit.

When you see multiple absorbs in a row, it's not because it proc'ed that many times, it's because it proc'ed once and the damage the mob dealt wasn't enough to deplete the shield.

When you see a partial absorb for a low number (e.g.: "xxx hits you for 5 damage (9 absorbed)"), it's not because it decided to only absorb 9 damage on that proc, it's because the previous hit(s) from the mob already would have done 16 damage.

Like most shield mechanics in the game, it's a bit buggy when you have multiple mobs hitting you at the exact same time. That is, they all -hit- you at the same speed and impacts are simultaneous. If the shield procs in such a scenario, it will absorb 25 from the attacks of all mobs attacking you.

Personally, I consider this a decent enchant for early leveling of melee characters as it reduced the frequency at which you have to bandage/eat. Also very nice for warriors tanking low level instances. At around 35+, its effects become negligible and unfortunately there is no upgraded version for later levels.

According to some mathcraft...
This enchant is better than +100HP to chest if you get hit more than 80 times/combat.
This enchant is better than +150HP to chest if you get hit more than 120 times/combat.

Most end-game boss encounters have a swing counter of 2.0 - 2.5 (with exceptions such as Prince in phase 2, etc). Most boss fights last from 5-10 minutes. Those numbers yield 300-600 strikes/boss fight. A significant mitigational upgrade over +150HP to chest.

Note: +150HP to chest is not buffed by Vitality or Blessing of Kings, as it's a pure HP increase, not a +stamina increase.

That's an interesting view on it... but keep in mind that tanks mainly want stamina/health not as a means of mitigation (they take far, far more damage than their health pool in a boss fight anyway) but to be able to survive bigger bursts of damage and periods on no healing. So you can't really compare the two side by side like that, they serve completely different purposes.