I just got the spear in my second play-through of the game - before heading into the Henne Mines after Mjrn. With a party ranging from level 20 to level 23, the hardest part was defeating the King Bomb and then racing into Nabudis and getting out again in roughly one piece. But now, after getting the 235 license points needed to use the thing, I've got Basch as a virtually unstoppable tank, felling most regular monsters in a single hit.
Quite fun, really.