I don't think it's worth using spiders in the form of Spider Queen. It is so slow :( By the time it reaches an enemy it mostly dies by then. The queen does aoe damage to those mobs whom are near to the queen. The damage did not impress me either.
It goes very well with anything that immobilizes, stuns, or groups enemies. Hex, Grasp of the Dead, etc. You want to work on concentrating enemies around the spider.
It isn't as powerful as Grasp of the Dead, but it lasts a lot longer and it does have an advantage over Grasp - it's mobile and it can be recasted anywhere on screen. It also lasts for a very long time. 20 seconds ensures that if you cast the spell when you have a lot of buffs on you, the buffed spell damage is carried over to the spider for a long time.
So... use it with Grasp, Hex, Soul Harvest, and Big Bad Voodoo.