Base comparison to Needle vs this repeater:
Originally Posted by Hendrik
An Artificer's conjured bolts take care of the weapon not having a +enhancement on it, but they lose the spell casting implement.
2.5[1d12] = 16.25 avg +7/8 3[1d10] = 16.5 + 0 (+6 if Pure Artificer)
Speed Modifiers: 20% alacrity (*1.14) 9% doubleshot (~4.5% since repeaters are less affected than bows)
Spellcasting Implement = 21/24 0
Hemm/Phlebot +2/3d8 Stat damage
Rogue Mechanics won't care about the Spellcasting Implement, but won't be able to get better than +3 bolts from House D.
My biggest quibble with this repeater is that it's the 5th named epic repeater. Epic Silver Slinger is niche and purpose built. Needle is pure damage. These three, Epic Doublecross, Slaver's Hand crossbow, and Trapsmith's all share a poison/stat damage theme. Stat damage is completely trivialized by Epic Ward in difficulties above Epic Normal.
So, basically, this new crossbow will clear up slayers the best, but Needle, even un-upgraded is still a better all-arounder (which maybe raid loot should be).