I picked up this belt last night http://www.wowhead.com/?item=32258 and just was comparing it to http://www.wowhead.com/?item=32339.

Why is 307 armor costing me 18 healing and 12 sta? They're the same ilvl, this doesn't make much sense to me. Could someone explain what I'm missing here? Or is the belt from supremus missing stats?

edit: I realize that one's leather and one's mail but it doesn't really make sense that I lose that much from going leather->mail.

One of those is misbudgeted. An armor value like that is an innate properly of leather/mail/etc. You don't get extra points on something just because it's leather.

Edit: Checking properly, either the leather belt is overbudget or the mail one is underbudget.

The mail belt just seems underwhelming next to the tempest keep one, thanks for clearing that up for me.

Yep, I have that same mail belt sitting in my bank because while spell haste can be nice, it's just too huge a sacrifice compared to the ilvl 128 belt I got from TK trash.

Yea, it doesn't really seem worthwhile to sac 14 mp5 and some +heal for .03 /.04sec off my heals. =/

When looking at the items that have spell haste on them, I don't see any that are really worth getting. Except maybe that trash ring, it seems really sweet.

The haste part just seems to be insanely expensive, at least for a healer. It's better for dps as they can apply the haste constantly.

Not sure if I missed it, but I didn't see a spell haste option on that calculator, is it valued the same as another stat?

All ratings cost the same amount.

Yeah, sorry I'll need to add the haste ratings to the calculator the next time it makes the top of my to-do list. I also have NO idea what the "Armor Penetration" or whatever we call it now is worth, thoughts/info?

The trash rings are ridiculously overbudget (intended though I think). At Ilvl 151 they are equal to Illidan and Archimonde drops.

I just plugged some items with armour penetration into the spreadsheet, entered their regular stats (except for armor penetration) and tried several values for resilience rating (or any rating really) until the calculated item level was close to the actual item level.

Coker of Serrated Blades
175 APen ~ 27 resil, http://www.wowhead.com/?item=32591

Shady Dealer's Pantaloons
175 APen ~ 27 resil, http://www.wowhead.com/?item=30898

Stormrage Signet Ring
126 APen ~ 14 resil, http://www.wowhead.com/?item=32497

The first two item give a 6.5 APen ~ 1 rating ratio, the ring gives a 9 APen ~ 1 rating ratio. Plugging in the 6.5:1 ratio into the ring, ti would be ~7 ilvls over budget, acceptable when you see other flukes.
I didn't find other items without socket to try, and backwards math with socketed items seems like a big "no go" these day.

Assuming a 6.5:1 ratio, you's need 15 rating value for 100 APen (+1% damage on cloth level targets), 24 rating value for 160 APen (+1% damage on heavy armoured targets, mail level or unsundered armoured bosses).
Sounds decent to me, not too good and not too bad.

Could anyone tell me where i could find the ilvl value for sockets?

I have looked at the original table of values and a couple other locations to no avail.

Or is there a comprehensive list that I missed somewhere?

For Mages, and other nuking casters, however, the value of Spell Haste is in that it scales tremendously with gear. I agree though, that it doesn't have as much value for healers.

I tend to disagree that spell haste is useless for healers. Look at the progression Blizzard has taken with healers.

Molten Core: lots of stats, a bit of +heal, a bit of +regen, nothing fancy.
BWL: lots more regen, introduced fights where you almost *needed* to do a healer rotation.
AQ40: tons more regen, balanced with healing. Finally stressing Mp5 as a primary stat.
Naxx: +heal scales a little better, but even more regen. Finally have the holy trinity: 10k mana, 150 Mp5, and 1000 +heal.

TBC: continues.

Now, look at *encounters*. What does TBC suggest to all of you? From what I've seen so far (3/10 T5 bosses down), they think we have enough regen now (it's tapering off / plateauing), they know we have enough +heal (easy to break 2000+ if you want to), and they recognize that neither of those stats scales in a satisfying way.

So they stopped, and thought about what could possibly make us lose fights now. We have lots of regen (Super Mana + Shadow Priest + gear = win), we have lots of +heal (so we can downrank for more longevity, or switch to high rank for our highest HPS) ... but we still lose tanks to burst damage.

And they can't make more steady damage -- that's been done to death (hello Rank 2 Heal, *cough* Naxx *cough*). They can't do more huge damage (at some point, they're capped by the stamina of the tanks). So they're increasing burst-y damage. Medium-to-large hits, but many of them, back to back.

And how do you deal with that? Crank up your HPS. +heal is a decidedly BAD way to do that. So they introduce spell haste.

If a paladin geared him or herself in all the spell haste gear available in BT+, with 2/5 T5, according to the math I did, you get Holy Light down to about 1.65 seconds cast. With over 2k + heal. That's a 7k heal, in 1.65 seconds. And that's the type of encounters we're going to see past BT. Burst damage, then steady sustained, then BURST, then steady ... burst to force us to wear spell haste so we can DEAL with that damage.

My 2c, anyway.

Pretty sure that this has not yet been reverse-engineered with complete accuracy. See Item Levels Revisited for the most recent discussion of the subject I recall seeing.

In Hyjal/BT they seem to be putting more emphasis on raid healing than tank healing from what I've seen/know, which allows classes to shine where before only Paladins held the top spot.

There is still a very big shortage on mana in several fights unless you overwhelm the encounter with healers, often requireing SP's in the healer groups to allow them to sustain it. Haste rating only makes them spend mana 'faster' which sure increases their HPS, but does nothing for HPM.
You could look into how many people use the max rank of their healing spells all the time, because I think quite a few [with the exception of Paladins] will downrank just a little.

They could of done with implementing a new regeneration stat for healers, something like [% of mana regeneration to continue while casting], or [chance to restore <x> mana on spellcast] which would of been around equal to that of haste for dpsers.

Anyway sorry for the slight derail, but yes it seems a very expensive stat and for healers its not close to being remotly worth it.