I know how everybody worships the Vampire Knives, but in my opinion......
The Knives are indeed a good weapon, but I think the reason why everybody likes them is because they possess a unique quality found on nothing else I know of: Life Leech.
I think that kind of dulls peoples' senses to some of the flaws behind the Knives:
1). Far, far lower damage than the Scourge
2). The Knives are a terrible weapon to use in narrow passages (like some areas of HM Dungeon for example).
To get the most out of the 'knives, you really need to be fighting hordes of enemies. The knives wreck face in things like Pirate Invasions, Solar Eclipse, etc.
However, the Scourge will rule anything underground. It does far more damage, can go through one block thick walls, and releases homing projectiles. You literally do not have to aim with the Scourge whatsoever. BUT, it is balanced in that it is not an AoE weapon; the Scourge is what you want when you are fighting a single powerful enemy. The Knives are what you reach for when you have a bunch of small fry you want to get rid of fast.
I find that it seems like Red wants to nudge us all into getting both of these weapons. Together, they are ridiculously powerful for any melee-geared character.
Oh, and... on the subject of golden shower...
I prefer Megashark+Ichor Bullets. Same effect, but you don't have to keep swapping weapons and/or spending Mana. 4k Ichor Bullets will mow anything down in record time.