On the EU beta where I played for the first time, teslas were the most op thing ever. With pure luck gear, and all stats to wis, teslas killed every normal monster just by touching them, and elites in about a second. You could just run through all the dungeons without touching the monsters by yourself. Only bosses required you to pop a supression/heal widget.
Piercing Flurry Bloodletter was still the number one boss killer though. At lvl 27 (it was the max level during the time I played) I was able to kill bosses up to level 30 in 5 seconds without taking any damage.