I saw some people talking in the warlock discord the other day about Demonology simulation. The suggestion was that SimC is the better choice, largely because of the APL(rotation). So, I investigated!
First, lets talk bugs. They're inevitable, no matter how hard we try to avoid them. I found a couple bugs in AMR (that were all fixed in an update about 6 days ago). I also found a few bugs in SimC, which still exist as of this post.
1.) I had Service Felguard benefiting from Left Hand of Darkness. Looking at logs, this doesn't happen in-game, so I fixed that.
2.) The Felguard has a damage multiplier in-game. At some point it was changed from 1.2 to 1.1 and I missed it. Pet buffs like this are hard to catch. I updated it to match in-game.
3.) Dreadstalkers have 83% of master's Spell Power as Attack Power. I had it at 88%, so damage was a bit too high.
4.) Doomguard wasn't doing enough damage when Supremacy was not the chosen talent.
5.) I updated Thal'kiel's Ascendance to pick up the Felguard's passive damage multiplier, which I verified from log data.
1.) Wild Imp Fel Firebolt damage is too high.
2.) Dreadstalkers aren't implemented correctly. They use Dreadbite too often and Dreadbite damage is way too high.
3.) Thal'kiel's Ascendance damage does not match logs.
4.) Service Felguard is benefiting from Left Hand when it shouldn't (same bug AMR had).
The SimC APL and AMR rotation were doing equivalent damage with one exception: I needed to make an update for players with Wilfred's Sigil of Superior Summoning. The cooldown logic was causing the Doomguard to not be summoned often enough with the CDR from the legendary. This is because in the rotation I had it checked as a cooldown to be saved for AoE/Execute, but once the cooldown becomes dynamic it was being saved too long. There is an "estimated cooldown" field that can be used to alleviate that, but instead I changed it to be cast as soon as possible with the legendary, which ends up being most optimal.
If you want to test the two APLs/rotations, here they are:
AMR Default Rotation
You will find that both of them do the same damage in most situations. The largest differences are with Implosion. The SimC APL makes heavy use of it when talented, but the AMR rotation does not use it very often. The result is significantly higher damage with the AMR rotation... because using Implosion is largely a DPS loss in many cases. It's fun for burst AoE, but it's just not that good a talent, unfortunately.
If you want to see a log comparison, I used this log for some testing.
920k DPS in the log, 905k DPS in the simulation.
All the damage on abilities match up nicely. This is a high-end parse, so as expected, it's towards the higher end of the standard deviation.