I just had a combat test against a superior number of ships equipped with missiles. My ships were equipped with lasers and GCs only, no missiles or fighters. Unfortunately, the enemy had a slight speed advantage so I was unable to catch any enemy combatants, having destroyed just two unarmed ships that were slower than me. Tested offensive FCS targeting at least...
I did not notice any difference in PD performance from VB6, really. We shot down about 1800 Size 6 missiles within ~48 hours of combat. My fleet was made of 4 CA and 8 DD, all packing some GC PDs. Not a single missile got through. At that point, enemy missile ships did not want to close range with me and escaped.
When my cruisers got in range of their main guns to an enemy 17K ton ship (commercial, as it turned out later), every 10 seconds (their ROF) one of the 200mm triple laser turrets suffered a failure, spending 350+ MSP instantly to repair it, each time.
That did not seem like 2% failure chance. Even if it's not turret based but based on the amount of guns, there were only 36x 200mm guns in my fleet that were firing. Over a course of 4.5 salvos, my cruisers suffered 4 turret failures, spending 1400+ MSP. That's super brutal. Especially if the AI is not affected by the same failures.
What is most strange is that I had not a single failure when the guns were firing in Final Defensive Fire PD mode.
Also, for now, you have to manually raise/lower the shields.