It's been a while since I've seen this topic up, and since I'm thinking about TRing my barbarian soon and answer to this would be relevant.
To wit:
The Barbarian Past Life feat reads that it grants +1 HP/level (I believe this is bugged and is capped at 5 or something; is that true?), +2 Intimidate, and a 1/rest clicky of Rage (+4 Str/Con, +2 Will) that lasts for 30 seconds.
It also currently grants a stacking bonus to all of your rages of +4 Str/Con, +2 Will and something like a +50% duration to your normal rages. Is THIS WAI? Is it slated for changing?
I will point out that the feat without the hidden portion is almost entirely useless: the clicky has too short a duration and is usable too infrequently to be worth a feat slot and the HP portion doesn't count as Toughness for AP or prerequisites so it can't replace the more useful feat either. In contrast, the Paladin PL feat overs better or equal DPS (+4 Str can be +2 or +3 damage depending on weapon type, while Divine Favor ends up at +3 damage), a better bonus on attack rolls (+3 vs. +2) and can last for up to around 10 minutes, and doesn't come with a penalty to AC or fatigue following.