When they added the Metamorphosis talent though, I have to admit I was intrigued by the Demonology tree for the first time. I mean, turning into a demon is just plain cool. Still, by then I'd been playing as affliction for well over a year and had no desire to raid or level as anything but affliction, it being my true love.
Lucky for us, they implemented this dual speccing shenanigans. So far, I guess it's been pretty helpful and hasn't changed the way we raid too much. If anything, its made it much easier as a raid leader. Now, when you might need that extra tank, you always get the question: "want me to flip specs?" My normal answer is "do whatever you feel comfortable with." We're not "hardcore" and, as such, I've never really cared what spec someone is, as long as they can get the job done.
Anyways, I digress. I merely wanted to point out that I'm trying out Abi's demonology spec. You can find it along with a wonderful L2Play raiding guide here. I'm using his 3-53-15 build as linked in his post. It's a Meta/Ruin/Suppressionforhit spec. It's also the one with the Demonic Pact talent since I'm not counting on being with an Elemental Shaman at all times.
I have a crap ton (or if you prefer metric, .907 shat tons) of spirit (the glyph gives me like 150 extra SP), so I may pick up another Life Tap glyph, though I'm debating because this spec is mainly for fun which for me means running around town as a demon at odd times. Thus, I may take the meta glyph along with Immolate and Felguard.
The rotation is actually fairly similar in concept to the affliction one. Both require you to do different things at low life (for demo the mark is 35% not the 25% for affliction). Both have a pretty simple "normal" rotation where you throw up some DoTs and S-bolt. This demo build adds what I like to think of as a "special" button. If you ever played old arcade fighting games, you may be familiar with the concept of a "special bar". It's kinda like that, in that it beefs you up, lets you preform a few special things, but doesn't complete change your current rotation.
I didn't get a picture, but here's how I set up my cast bar from left to right (1-5): Corruption, Shadowbolt, Immolate, Curse Choice, Soul Fire. (Recall that my Affliction bar looks like: Corr/alt-CoA, S-bolt, UA, Haunt/alt-CotE, Drain Soul). Thus, I'm almost hitting the same buttons in the same order when I swap specs and bars. The rest of the bar has some of my demon form stuff and Rain of Fire for my AoE button (always 8 on my toons). It also has my Life Tap macro on 0 which is the same (lets you LT normal and hold shift to get your fel armor on). Then I have some clickable buttons around for the "cooldown" spells that I want to watch/click.
The point here is that I find it a lot easier if you can try to put similar spells on certain buttons. My DK even sort of reflects this so that I'm nearly hitting the same buttons in the same order. That way, if I have a brain fart, I'm not completely off and it seems easier to fall into a new routine.
I love having both intercept and charge too. I was always jealous off others having things to make them speed up when warlocks only get to run around at one friggin' speed. The best we could hope for is to swim faster in water with a glyph, which, lets face it, is completely worthless. Others can run on water... we swim fast with a glyph?
Anyways, I don't necessarily plan on using this for raiding right away or anything more than just making the dailies more interesting, but it is certainly a fun spec. Abi does a wonderful job of telling you "how to" loose your inner demonologist, so I won't rewrite what's already been done better. I just wanted to point out my initial thoughts about this spec and have an excuse to link this completely awesome picture:





