150 health or 15 defense rating?

Hello,
was wondering which one after 2.4 is worth more bang for the buck? the 150 health is static and isn't affected by anything and well... it does stack up but would the avoidance from 15 defense outweigh its uselessness or not?
Mostly tanking trash since i am not as geared as the maintanks, but i maintank in kara/za

I remember hearing this from someplace that 3 defense is worth as much as 2 stamina... or was it the other way round?

There's already a thread discussing this topic with a lot of good info in it for you.
_________________
Mavrix
BE Tankadin
Dalaran

http://www.wowarmory.com/character-sheet.xml?r=Dalaran&n=Mavrix

....But since I can tell you're lazy like me

15 Defense if you need the avoidance

150 Health if you don't

Hope that helps