Inspired by Alwar's chat message, I decided to look up some information about Crit and Haste. Both of these stats are B stats, and no self-respecting resto drood should stack for either of these at the expense of a greater stat, like spellpower or intellect. This is simply because resto druids use HoTs more than any other class, which have no cast time for haste to work on, and can't crit. That's looking at it simply however, and if you look deeper, there certainly are benefits to both. So if you're looking at two pieces of gear with very similar main stats, but one has crit and the other has haste - which one should you choose? Let's look at the pros and cons of both.
Haste works in three different ways. It reduces your global cooldown, it reduces your cast times, and it reduces the amount of time of time spent on spells that are channeled.
1. Reducing your global cooldown.
First off, what *is* a global cooldown (GCD from now on)? When you use an ability, whether it be a casted spell, a energy using stab, an instant heal, whatever - it triggers your GCD. It's the little "clock" animation on all of your spells that's set off every time you cast something. It's also the reason that you can't spam heals as fast as you can hit buttons or click a mouse (Apologies for the crappy arrows drawn in paint. I know, you can barely see them. The picture is just plain awful. I should change it, but if I work in Paint one more time I'm gonna cut a biotch).
GCDs are typically 1.5 seconds long. You can reduce this GCD down to 1 second with haste and talents, but you can't get the GCD lower than that. One main exception is Nature's Swiftness. NS doesn't trigger any kind of GCD, which is why you can hit it and then *immediately* afterwards hit your healing touch.
With the talent Gift of the Earthmother, a druid's GCDs of instant cast heals are reduced to 1.2 seconds. Any other haste that you have will contribute to reducing this GCD even more. However, as you get closer and closer to a 1 second cooldown, you'll need more and more haste to give you the same reduction. I don't know exact numbers, but I do know that to begin with, you need 32.79 haste rating to give you a 1% reduction (so, .015 seconds) of the GCD. But as you gather haste and reduce that GCD, the last .015 seconds to get it down to 1.0 seconds might require like, 100 haste (up from 32.79). I mean, don't quote me on that. I know that there are diminishing returns; I just don't know the extent of it. I *do* know that you would need quite a bit of haste to get that GCD down to 1 second - a rating of 500 or more, I believe.
Summary: reducing your GCD with haste is pretty rad because it means you can put more HoTs on people in a shorter amount of time.
2. Reducing your cast times.
Now certainly, druids are super HoTastic, but that doesn't mean we don't have *some* cast times: Regrowth, Nourish, Healing Touch. HT shouldn't be an often used spell, but Regrowth and Nourish can get some pretty good use.
Your %of spell haste = your haste rating/32.79.
Let's say I have 200 haste rating. 200/32.79 = 6.1% spell haste. Meaning that if I have a cast time like Regrowth, which is 2 seconds long - with 200 haste, that cast time would be reduced by 6.1%. Which in this case, 6.1% of 2 seconds is .122 seconds. (2 - .122) = a new cast time of 1.878. With a decent amount of haste, you could get Nourish close to 1 second and make it a really zippy heal.
Summary: Reducing your cast times with haste is pretty rad because it means you can put more heals on people in a shorter amount of time.
3. Reducing the amount of time spent channeling spells.
I'm not going to spend a lot of time on this one here, because really we have only one channeled spell - Tranquility. Yes, if you have haste, it will reduce the time it takes to channel (but it won't reduce the actually healing done - you'll still put out the same amount of healing; it will just be done in a shorter period of time). So sure, haste is good to have for tranquility as well =)
Critical strike chance (typically seen in the form of a percentage) is the chance that you will put a heal on someone that will hit them for roughly twice the amount it would normally. If you have 10% crit, then technically, 1 out of every 10 direct heals you put on a target should crit. Healing Touch, the initial portion of Regrowth, Nourish, the bloom on LB, and a swiftmend all can crit. HoTs however, cannot crit.
Because HoTs can't crit, many people initially think that crit isn't great for resto druids. However, I beg to differ - especially with the changes coming in 3.1.
Reasons crit is awesome:
1. Living Seed: This talent doesn't necessarily account for a significant chunk of our healing, but it definitely is dependant on crit, and is a nice buffer especially for tanks who are taking constant damage.
Side note: I was looking through some other classes' talents, and it struck me that druids only have one talent based on the formula "If you crit, x will proc". Fire mages have three of those: Ignite, Master of the Elements, and Hot Streak. Holy Paladins have two, Infusion of Light and Illumination. It makes sense that we'd only have one talent based on crit (I think it would make sense even if we had none), simply because most of our heals aren't direct crittable heals. Interesting.
2. Regrowth: If you take the talents in Improved Regrowth for the extra crit, this spell can be fairly formidable. It's too heavy handed to use for trash healing and most raid healing, but to bring a tank back from near death with a 9k Regrowth crit PLUS the tick afterwards - now that's a good feeling. Yes, the Improved Regrowth talent is being nerfed in 3.1, but it doesnt change the fact that Regrowth is a still a strong heal that's got a decent chance to crit.
3. Nourish: This spell just keeps getting more and more viable, especially come 3.1. Blizz is buffing its crit chance by 25% by throwing it in the Improved Regrowth talent, and the fact that it scales with HoTs is, well, pretty hot.
4. The BLOOOOM. Guys, after 3.1, this thing could crit for 18k. Hell, with better gear from Ulduar? We're talking over 20k here.
As in, disgustingly AWESOME.
I mean, I know that most/all of that will be overheal, and I know we'll all be out of mana by the time it blooms anyway (lol), but- but - 20k!! Just the number itself makes me giddy.
So where does this leave us?
Both haste AND crit are important to have. Crit will do nothing for your HoTs, but haste will shorten their GCD. Haste does nothing to help you land those crazy big heals, but after 3.1, a lot of crit will make your 3 stack of LB bloom for 670k. Not really. But close to it. Kinda.
Haste allows you to cast more spells in the same amount of time it would take you to cast less spells. Crit allows you to sometimes cast twice-as-big heals. So I would say, get a bit of both. Personally, I like haste - I'm an impatient little bugger and hate waiting for cast times and GCDs. I also like knowing that yes, my Regrowth *will* be .2 seconds faster every time I cast it. Every single time. What I *don't* like is wondering if a spell is going to crit or not. But when it really comes down to it, I never select a gear upgrade based on the fact that it has haste. If it's an upgrade in stats, then I'll consider it, and if it happens to give me crit, or haste, or whatever, I figure, hey, it'll balance out in the end.
TL;DR: Haste is better than crit for resto druids, but not by much. Crit is going to get better after 3.1 with Nourish and teh bloomz getting buffed. However, I still think that haste will take the cake.
Have any of you geared specifically one way or the other? I'm curious to hear what you all think of crit and haste.
ALSO: Check out Syll's post from Rolling Hots about crit here. It's a great resource for all your crit-related questions =D