From progression point of view...
what seems to be more rewarding/ less punishing for healers
what I have is (all values unbuffed)
set 1: ~37.5 k hp unbuffed, 1646 SBV, 4% hit, 28 exp, 23%/ 20.4%/ 21% (dodge/parry/block)
set 2 (aka: heroics/trash): 33.4 k hp, 2275 SBV, 6,83% hit, 13 exp, 21%/ 18,5%/ 23,2% (dodge/parry/block)
should I go for items which are generally an upgrade (iLevel-, tankpoints-, EH-wise) or should I try to maximize SBV?
with time I bet I can do both but for now... gotta choose...
(ulduar10 hardmodes, ulduar25 - no hard modes, pretty much casual guild - trying to sway them to do SOME HMs at least, colloseum - will do 10 HMs for sure, maybe a shot @ 25 HMs)
SBV is nice for trash, adds, and some bosses hitting like weak noodle - Brundir for example. When tanking anything that can kill you, like XT hm or Steelbreaker hm, you should go for EH. Since we have no way of guaranteed block outside of SB uptime, you can and will be hit for maximum damage, and it can and will happen twice or three times in a row. Better to have enough EH to survive that.
it's just this prot pally we have who bragged about having ~3,8 k SBV that made me think... though the pally gems for hit, enchants for hit and has like 5k hp less then me... still... so angry when he pulls aggro off without even trying :<
I don't think until block is truly changed it will ever trump health and avoidance in the current content style, at least for bosses. Even on a critical block the amount blocked it pretty insignificant compared to incoming damage.