Microwaves are brutal, but I think I did do electronic hardening level 1. Which... should not actually be visible in the design screen, so, heh, it would hurt a lot. Thankfully, the ECM should give me a chance. But yeah, at this low BP and RP, mesons are absolutely brutal. I defeated a fleet of invaders with them once-- sure it took like 300 fighters, but still.
The thing I don't like about microwaves, is that they very rarely create secondary explosions. Hitting an ammo rack with mesons has... explosive results. But another one of my favorite tactics is blinding the designated targetting ship with microwaves while missiles are in flight.
Imagine getting blindsided by a fighter moving at 30,000 km/s and blasting you with microwaves and then just running off. And by the time your sensor is repaired, there's a fleet with 35cm railguns in your face.
EDIT: Oh, I forgot I added Microwaves as well. Good thinking, past Thanatos. Good thinking. Now, if only I would stop forgetting putting fuel tanks on my Campaign ships.