Shooting from the hip, I'd say the sacred shield might be better. 7 more all res, more life, and significantly better blocking (stormshield blocks ~5% more often but the sacred blocks ~25% more damage).
And doing some fiddling with my spreadsheet, it looks like the stormshield probably gives you an ehp advantage vs elites' melee attacks but probably a slight disadvantage vs elites' non-melee attacks or melee attacks of other creatures, and a stronger disadvantage vs non-elite ranged attacks. My methodology may be (probably is; no breakfast or caffeine yet) slightly flawed, but I still think the sacred shield is a better choice. I bet it is cheaper, too.
I just replaced the dodge portion with the melee DR, elite DR, and 1-(1-melee DR)*(1-elite DR) in three different rows, assuming some typical barb base stats (40k hp, 9k armor 900 res) and modifying them by the differences in the shields. There are much more sophisticated spreadsheets out there, but I made this one and it is simple and quick to use (if not very flexible) so I continue with my folly.
Ooo... I'm seeing some room for significant error. Uh. Can you just tell me your actual stats with each one equipped since you have them both on hand? Hp, armor, lowest res (or average of your resistances, or phys, whatever you prefer)?
I think the sacred shield is a better all-around shield. If you are using Justice Lantern and Helm of Command, that 2% blocking difference is pretty insignificant since it would be 45% vs 43% block chance. Even if the Stormshield has a slight edge against elite's melee attacks, it's going to be inferior in every other circumstance.