I've been very successful with the following list:
5x Gamma Squadron Pilot + Seismic Charges
It's a very intimidating list, as they don't want to get behind you. The bombers move at PS4, so you get to choose to drop a bomb after their lower PS ships have moved. That's really nice to know whether you can drop a bomb or three on them when you know it'll hit. Further, they have 6 hull, so they are tough to kill. They still get the 2 Attack Dice, which isn't bad when massed fire, especially on B-Wings or Y-Wings.
I won a Store Championship with this list and it's gone 8-0 in my league.