I have a question about the new shield enchants.

Enchant Shield - Tough Shield: Permanently enchant a shield to give 18 additional block value.
Enchant Shield - Shield Block: Permanently enchant a shield to give 15 block rating.

Which one is better? What is the difference between "block value" and "block rating"? I have a feeling that Enchant Shield - Shield Block is the better enchant as it is a higher level enchant and more expensive but I don't understand why. Any ideas?

Which would you go with or would you rather use one of these?

Enchant Shield - Resistance: Permanently enchant a shield to increase resistance to all magic schools by 5.
Enchant Shield - Major Stamina:Permanently enchant a shield to give 18 Stamina.

I'll get beat but here goes:

Block value is how much damage you "block" when you get hit by a mob. Ex. - Mob hits for 200. You block. Well, if your block value is only 198, you take 2 damage (in the rawest sense).
Block rating is how often you are going to block.

I've gone the Major Stamina route so far just because 5 resistance is quite paltry and additional block rating and value so far hasn't outweighed the static hp gain I receive from stamina.

Block rating equates to %chance to block. At level 70, 15 block rating equals 1.89% chance to block an attack with your shield.

18 block value means its 18 additional points added on to the amount that is blocked by said shield. It also adds to shield slam damage.

I personally have been adding 18 stamina to my shields.

Good answers. Thanks alot. I think I will go with stamina for now.

Stamina my friend. Stamina.

The way I always looked at it was Stamina first - Then once you had good enough gear, and large amounts of HP (Large enough so that your healers had a fairly easy time healing you.) Then you could switch over. Way back in MC I had Stamina enchant at the start, but towards the end of BWL I switch over to the block as I'd gotten much more of a HP pool.

Is blocked damage before or after armor mitigation/def. stance?

I'll save the stamina enchants for the resistance shields, ~189 hp is under 2% of my base HP. You can buff HP with alchemy, food, and spells whereas sustained mitigation is harder to come by.

I'd go with physical mitgation on the heavy duty tanking shields. I suspect I'll be putting +block value on my shield since it is harder to get than block rating, and I also have the ability to bump up my block rate for 2 attacks every 5 seconds. There is no incremental value to being over 100% block, so the 1.89% really only applies to a small number of incoming attacks. Unless it's multiple mobs or something that attacks really fast, I'll probably have shield block up for the majority of the incoming attacks that could be blocked. It's more likely that I'll want more damage blocked than I'll want a higher percentage of attacks blocked.

Noone has mentioned shield spikes yet. Though I love block value on everything else, I think shield spikes are a superior enchant on a shield. If you just get initial aggro (Being the puller, demo or battle shout) the spikes alone can outaggro a healer if you don't take too much damage. This is great for AOE type pulls if you don't have an AOer.

It is a small but noticable damage boost when fighting one mob. But when fighting lots of stuff, like the adds on fankriss it becomes a big boost. Thorns, retribution aura and most other retribution type buffs only deals damage if you actually take damage. But shield spikes deal damage on every block - even a fully blocked attack.

The only correct answer is stamina, because the rest of the encahnts are stupidly expensive.

I don't really consider the cost of an enchant important. If you want to be the best, the gold it costs shouldn't matter to you. It's only when you start to settle for second bests when cost starts to matter ;)

Well 12 Int is allready a step up. But i suspect we are limited by the fact that their is no off hand enchants at all.

Well, assuming it does work that way, it's really not difficult for a Prot paladin to reach 40% base miss+dodge+block+parry. Getting to 490 defense alone will do it, and you'll want that anyway for crit immunity. If you pick up Deflection, you don't even need the 490 defense. The other theory is that you're only crush-immune if you have a 100% block chance, in which case it's not even worth trying to get that as a paladin, as you'd need 35% base block in the best possible case (using the epic Holy Shield-boosting libram), and that's simply not doable. So either way, this enchant isn't going to be much good to a paladin on the crushing-blow front.

There might be significant value to a paladin stacking block rating or value against AoE attackers or fast-attacking mobs (e.g., Romulo) but I'd want to do more theorycraft (or hear of actual results) before I dish out substantial materials for one of those enchants.

For now, I'm going with +18 stam as a safe default choice. Besides, I already lose 1.2k health to a warrior before we put on any gear, so I kinda feel like I can't afford to pass up an opportunity to get more stam.

You sure?
490 def = +22.4 % (miss + dodge + block + parry)

Can you talent spec the missing 17.6% ?

EDIT: I guess I forgot the base chance ^^

I'm probably going to roll with a +block rating on my BQB. Block value outshines anything else by far for trash or aoe tanking, and as a paladin I figure I should play to my strengths. Once I get a nice TBC shield with tons of stam on it, I'll probably add more stamina - that cushion zone is crucial for tanking anything hard hitting. So, my vote is, get two shields, and use whichever the situation calls for.

From a shaman PoV: I do stamina just because I never valued int as much as I valued HP once I started raiding. When your gear gets better and better, the amount of mana your m/5 and potions regenerates starts to outpace your initial mana pool by a great deal, virtually making a slightly bigger mana pool less essential. This isn't quite as true now since we gained a lot of base mana from leveling, but m/5 still leads mana pools for me and personally, stamina will never be worthless in large-scale raiding. Especially when the first serious raid encounter is Gruul.

At the risk of sounding stupid, don't you only need 100% combined miss, block, dodge, parry to be crush immune? This was the reason that I always thought increased shield block percentage was one of the most overrated of the mitigation stats, even a ham sandwich in 20man level plate has 25% miss, dodge, parry, block. You only stack high block percentage against boss's that are capable of putting out 3 or more large attacks in 5 seconds so that you reduce the risk of a crush on that 3rd hit (or if you are arms/fury specced I suppose.) Personally, I liked to keep around two shields so I could switch based on how "melee" oriented the boss was.