I’m not sure why SimC is preferring less haste for BM than we are. also, we don’t really use “stat weights” anymore because they’re pretty coarse and basic compared to our more advanced gear ranking techniques.
In general: If you do a single simulation with AMR and SimC you will get a result that is very close/similar. This is expected if both simulators have the game modeled correctly. The stat weights that simc calculates uses a very, very basic method that only looks at 2 data points per stat. We generate thousands of data points and from that create a predictive function for the stats. It is a much better predictive model of what stats will give you the best DPS - and our function can adapt to your item level. SimC/Raidbots puts almost zero effort into actually analyzing the data. AMR is all about analyzing the data.
We have some forthcoming blog posts where we’re going to try to explain it… but, using single data points from simulations to compare gear isn’t a statistically valid comparison. If you simulate set of gear A and set of gear B and A does 1% more damage than B in your two results… that doesn’t tell you to use set A. That tells you it doesn’t matter if you use set A or B. It doesn’t matter what margin of error(iterations) you use for that test, they’re too close to distinguish. Simulators are good to generate large sets of data to be analyzed for trends. They are not good for “point comparisons”. The main reason for this is because WoW simulators in particular do not exactly model the game they are simulating. It is not possible to measure the error of the simulator compared to the game.
An example of perfect knowledge causing what I believe to be unrealistic sim results is how SimC APLs make liberal use of functions that check when the fight will end to decide how to time up/sync cooldowns. A lot of that logic depends on knowing exactly when a fight will end. Players cannot know this exactly. At best… maybe you can guess within 15 seconds? Depends on your raid group. But there are lots of rotation tweaks in SimC that end up getting one more fractional use of a cooldown because of this knowledge. I could do that in the AMR simulator, but I don’t. It’s not real.
Another difference is that we make all of our gearing strategies on fights with realistic amounts of movement.