As I've often said, I play almost exclusively using 2-shot missiles in the early/mid game.
If using a custom OP race, the games rarely go much longer than that. I'll switch over to beams (Death Ray) if I've taken out the Guardian early (thx EMG). So my ships aren't designed to last in battle until I have some powerful beam weapons so I don't have a computer or battle scanner onboard so PD is just a waste of space. I also won't usually research shields until Class V.
However, once I am making beam ships which need to last, then some PD is useful if the enemy(s) are using lots of missiles or worse yet, fighters. If you get Particle Beam from Orion, that makes an excellent PD weapon, noting that 15 space for a regular PB becomes 7 for the PD version. PD Phasers are also good and will miniturize.
PD Mass Drivers can be useful due to no range dissapation. In my Mrrshan game I went for Mass Drivers early on to take advantage of +50 attack and since my main enemy had ECM. My ships were about 75-80% Heavy MD's and the rest PD. Since there were many fighters coming at me, I could use the non-targetted ships' PD to help destroy them by moving them up next to incoming fighters. PD was useful then, but these ships and with Class 3 shields were designed to last a few turns in battle so as to fire many heavy MD's.
In my Bulrathi game (I won one for once) I'd allready taken Orion, but didn't have Particle Beam. I honestly made an Assault Shuttle Ship once the Antaran attack was coming (nice to have a 5 turn warning) and used it to capture an Antaran ship (first time I did this in years) and scrapped it to get Particle Beam for PD use.
I recommend some PD if the enemy has EMG as you don't want to be hit by EMG missiles, especially if using Damper Fields instead of shields.
PD with a poor computer or without Battle Scanners doesn't seem to hit too often. I've seen my PD in my Star Bases early on be ineffective w/out Battle Scanner, noting that I usually won't research a good computer until the last one since early play is with missiles for me.
.. neilkaz ..