It's good, even at 60. You should save up for JBB while leveling if you solo a lot. A JBB will help you more than your stat gear, so it is definitely worth selling the stat gear for it.
https://www.youtube.com/watch?v=umuVBewCNgY - At 60 doing Cliff Golems I can get 5326 damage from it, which equates to 1/6 of the Cliff Golem's HP. Mana-wise that is saving you at least 1200 mana from casting Pox, not including potential resists and casting insidious decay.