The Picksaw is a drop from Golem, one of the four bosses introduced in the 1.2 patch. Holding an amazing 210% pickaxe power and 125% axe power, it is the second strongest mining Pickaxe available, with the luminite picks having the highest pickaxe power. Although the Laser Drill has 20% more pickaxe power, it is a Drill. Having a speed exceeding that of the Drills and Chainsaws (Very Fast), it is the third quickest mining tool, just slower than the Shroomite Digging Claw and Drill Containment Unit and its +1 Range surpassed by the Spectre Pickaxe.
It is the first pick with the ability to break Lihzahrd Bricks as well as the Lihzahrd Altar. The best prefix this tool can have overall is "Legendary". The best prefix for speed is "Light".
It should be noted that while this tool doesn't have the highest pickaxe power, it also possesses a high axe power as well, making it a handier tool for general mining and building than the four luminite pickaxes (Solar, Vortex, Nebula, and Stardust). There aren't any blocks that this tool cannot mine just as fast as the higher powered luminite ones.