Before you skip to the comment section and /rage here, I'd like to state for the record, I do believe simcraft to be a useful tool for warlocks. That being said, I think a lot of you are doing it wrong.Simcraft "is a tool to explore combat mechanics in the popular MMO RPG World of Warcraft (tm). It is a multi-player event driven simulator written in C++ that models raid damage and (in the near future) threat generation. Increasing class synergy and the prevalence of proc-based combat modifiers have eroded the accuracy of traditional calculators that rely upon closed-form approximations to model very complex mechanics. The goal of this simulator is to close the accuracy gap while maintaining a performance level high enough to calculate relative stat weights to aid gear selection"
So simplify, simulationcraft is a program you can use to enter your characters information to and receive statistics and charts for just about every scenario you can think of. You can also tweak your base gear stats to compare possible upgrades and plan your future gear. While this is all very excellent, I personally think there is a problem with the warlock community in general when it comes to use of this tool. I believe it's a two part problem.
The first problem with improper simcraft use is the program can not factor in personal playstlye in the sense of strengths and weaknesses. Simcraft may tell you your maximum possible capable damage output with your gear would come from a certain spec, while personally, you may not be so well versed with said spec. I've had a few guild warlocks who have simcrafted demo as best for their gear, but can't do a thing with it. I myself have done everything according to the books, followed simcraft, and went demo only to take a significant loss (and I mean significant, much more then you should) in performance. Even with most of the bosses well within soulfire execute, the tree is just not clicking for me. I have no regret at all going against the system and choosing a spec I'm much more comfortable with in affliction. While I pride myself in giving all possible specs and builds a fair chance with substantial testing, there's just no denying I have much more of a knack for affliction. after 3.3.2, I'm going to upset a bunch of number crunchers by saying any warlock out there is likely doing themselves a favour by going with whatever tree they feel like. Provided you aren't completely crippling raid composition (Still nice to have demo on board) you will probably be just fine pew pewing however you see fit. The trees have never been so close to balance before, and it's throwing undecided warlocks for a loop. Asking which spec is best at this point of the game is a pointless question to me, they're all pretty good. The real trick is, learning how to use it. Personal experimentation and practice are key.
The other problem with relying to heavily on simcraft is that it's a simulation, and you are not a robot. The program calculates all possible outcomes on various encounters where a) all raid buffs are present (which can also be customized, yes) and b) you are executing to perfection. Anyone who has ever spent a lot of time raiding in WoW can tell you, things don't always go according to plan. Sometimes, it hits the fan, and to survive like a good raider, you have to move your but or cast something on the fly to compensate. This will always affect your numbers, and you should be ready for that. Don't panic when your personal numbers aren't matching simcraft, you are an absolute machine if they are. Simcraft is more of a benchmark to aim for.Demonic Hobbs has recently put up an excellent post about the proper instruction and use of Simulation craft. If you are interested in possibly using it yourself, I highly recommend you read it over. - [Link]
Now this is more of a personal beef, but it's quite related. As you may know, I frequent the forums at The Warlocks Den and much like the word of the minute last year was "Viable" it seems this year it has to be "Simcraft". The reason I go there is to converse with others interested int he dark arts, see how they are doing things and finding out what works for them. Instead, thread after thread is clogged with simcraft says this, simcraft says that. If I wanted simcraft numbers, I'd have conjured them up myself in my own lair thank you. I'm more interested in what actually works out there in the real world!
Sorry for that last little bit there, but I had to get it out of my system. To summarize, don't get carried away with the numbers. You have to know how to use them wisely if they are going to benefit you, so just start using your head people! I don't discourage practice and experience with other specs when I say all of this either, I just pray that some people out there aren't just using a spec after 3.3.2 because simcraft said so. If I've encouraged anyone to be bold enough to go against the charts to do something they have proven through personal experience to improve their performance, my work is done.