Armor should never really be a stat that you prioritize around, especially with a 15 ilevel drop. The haste on the shield is nice, but the vers provides a raw healing increase and global (all types) damage reduction where as the armor is strictly physical. There really isn't a whole lot that the shield will do for you in Blackrock unless youre actively tanking hits from something... in which case get a bop or call for your tanks to stop being bad at their job(or you for not keeping a tank alive long enough to do his job effectively, I guess. Can't always blame them, though they are to blame most of the time.)
Go with the offhand.