The Raid SS's are a bit weird these days. Sometimes (but rarely) they do mad quick strikes and take out a Command Station, then run. Other times, which is more common, they pick weird targets.
There was this one planet in particular in a game I'm just playing. I had a mk1 econ station, mk2 FF, mk2 and mk3 reactors, and some miscellaneous turrets in the location. The Raid SS came in. Shot at the FF a few times. Then shot at a Laser Turret once, Then started shooting at the mk3 reactor, kept shooting and destroyed it, fired on the FF again, the laser turret, then the mk2 reactor, destroyed it, and ran away to shoot some random turret on the other edge of the planet. Then my backup fleet arrived and eliminated it.
Weird.
When there's a lot of them though, I tend to rely on a combo of Heavy Beams and Grav Turrets, so that I can keep starships mostly on offense. Gravs give the Heavy Beam plenty of time to shoot down a few Raids and Leeches.
I play mostly on Diff 7, but I'm thinking about moving to 8 soon.