The droid gunship looks like an antlion. It's a cool piece, but it's ugly as sin, and is more Episode III than I can or want to handle. LEGO could have chosen something more from Hoth or from Jedi - anything but from Revenge of the Sith.

Even Jay's Brick Blog has little to say about it.

STAR WARS Advent Day 1: Slave 1
STAR WARS Advent Day 2: Bespin guard
STAR WARS Advent Day 3: Tie Interceptor
STAR WARS Advent Day 4: Imperial Navy Trooper
STAR WARS Advent Day 5: Hoth Defence Turret
STAR WARS Advent Day 6: Snowtrooper
STAR WARS Advent Day 7: Snowman
STAR WARS Advent Day 8: FD P-Tower
STAR WARS Advent Day 9: Hoth Rebel Trooper
STAR WARS Advent Day 10: Venator-Class Star Destroyer
STAR WARS Advent Day 12: Droid Gunship
STAR WARS Advent Day 13: Battle Droid
STAR WARS Advent Day 14: Obi Wan's Jedi Starfighter
STAR WARS Advent Day 15: Tantive IV
STAR WARS Advent Day 16: E-3P0