Lazer heads have been working for the entirety of version 6. I think they may have been broken back in 5 but every time I've tested they have worked well. They're excellent as standoff weapons to get damage past something with excessive but short ranged point defence.
Great!!
I actually never used them.
Oh... and regarding missiles. Even if I think that armour on missiles could be implemented better... at least improved with armour technology it is a viable way to protect missiles. I also think that agility should be as important as speed for a missiles ability to evade AMM. In reality missiles use both speed and agility to evade AMM.
If enemy missiles already have a high hit chance then increasing speed is pointless... it is much better to reduce speed add armour (and agility if necessary), This will make anti-ship missiles cheaper and able to withstand AMM better even if they have 100% hit chance. If you also use a combination of fast and slow missiles it will be harder for the enemy to tailor their AMM to a certain type of anti-ship missiles.
In multi-national campaigns I find it very important to use multiple type of ammunitions, attack forms and strategies since being predictable is NOT a good strategy, simply too easy to counter.
I also find that, in most cases... it is the scouting element that determine who win an engagement. Full on engagement between fleets are only happening when the stakes are really high. That is if you role-play the political reasons why you fight and the need to preserve forces in most situation. Very few battles will be to the last ship, even in beam combat.