I am using the paid version and there is one glaring mistake with the Subtlety rotation. It all works rather nicely (hemo debuff uptime seems fine) except for Ambush and the management of the Find Weakness debuff on the targets.
When you use Shadow Dance or when you Vanish or start from Stealth with the talent Subterfuge, it will not keep casting Ambush and will instead use Backstab. It only uses Ambush once.
You need to use Ambush as the combo point builder anytime it is available, always, even if it costs more energy than Backstab. If Ambush is available, it HAS to have priority over Backstab. Another thing that is important to note is that you need to maximize your Find Weakness debuff uptime on your targets... so say you start the fight, it uses Ambush (that's correct) and should keep using Ambush until Subterfuge runs out. After that it should use Backstab until the Find Weakness debuff drops. As soon as it drops you need to cast Vanish and Ambush again, repeating your initial rotation. After Find Weakness drops again, immediately cast Preparation, Vanish and do the initial rotation again.
After Find Weakness drops and Vanish and Preparation are on cooldown, use Shadow Dance and keep spamming Ambush (this is the worst mistake of the bot atm). Right now it is casting Ambush only ONCE and using Backstab while Shadow Dance is up, which is very... very bad.
So to recap, Ambush should have priority over Backstab ALWAYS no matter what. Preparation (to reset Vanish) and Vanish should be used whenever the target doesn't have the Find Weakness debuff. Also, if you can add this... finishers also have a best way to be used. You should never refresh Rupture if the target has the Find Weakness debuff. Refreshing Slice and Dice should always be #1 priority but Rupture should only be cast if the target does NOT have the Find Weakness debuff... if it does, the bot should always Eviscerate.
If you have any specific doubts let me know and I can help you with making a perfect Subtlety rotation.