I played my first game with Y-wings last night and they wiped out the opposing TIE fighters. We played 60pts per side, with the Imperials having 4 TIEs against the 2 Y-wings.
The Empire fielded Dark Curse, Winged Gundark and 2 Black Squadron pilots, with the Rebels having Dutch Vander(Ion Cannon and R5) and a Gray Squadron pilot(Ion Cannon, R2 astromech and proton torpedoes). The TIEs closed fast and tried to overwhelm the Y-wings defences, but the ion cannons were worth their weight in gold. They hit each turn, which allowed the Y-wings to stay out of the fire arc of 1/2 the TIEs each turn. Concentrated fire killed Winged Gundark on turn 3, a Black Squadron on turn 4 and Dark Curse on turn 5(proton torpedoes as he tried to extend the range).
End result was 3 TIEs destroyed with the last one having 1 hull point left. Dutch Vander had 1 shield remaining while Gray squadron had taken 1 hull hit. It was the first time either player had faced or used ion cannons, so probably a one off win, but it was fun.