Is it really that good? I hit 52 last night so started using Smite - every time I look at Sidearm I can't see the appeal. :/
The reason why Sidearm is so good is because it hits for the full weapon damage of Frenzy - 110% weapon damage. Every time you hit with Frenzy, you get a 15% speed increase, up to five stacks. Sidearm has a 25% chance of activating. If you're hitting Frenzy as much as possible, it's a nice way of saying you have a 1/4 chance of hitting
everything in your path.
For full damage.
Now imagine that with Battle Rage (45% damage increase, plus crit increase)
Now imagine that with Wrath of the Berserker with Insanity (100% damage increase plus TONS of additonal stat increase)
Now imagine those two together with Ignore Pain plus Ignorance is Bliss, which gives 20% of all life back for all damage you deal.
With a slow two hander at level 56-58, Hell difficulty, you're effectively smacking almost every single enemy in the room for around
35,000 per hit. And you're healing for roughly 20% of that thanks to Ignore Pain. And that's not even accounting for Revenge, which is also benefiting from Wrath + Battle Rage. And you're also getting health back from it.
That's why Sidearm is so good. The extra damage is just insane and with the right abilities and equipment you're unstoppable for as long as Wrath of the Berserker holds out and you have a target. And if you don't believe me, just check out Kungen's streams. He's effectively using the same setup as me, except with a one-hander + shield on Inferno. It makes slaughtering most champion packs pretty easy.
Unless you're going for a kite build, or you simply can't take any hits at all, Frenzy w/Sidearm is without question the best choice.