Tadrinth, I imagine its danger varies significantly with difficulty. I encountered a wrath lance guardpost in my (to date) only victory, on 7/7, recognized it as the greatest threat, and killed it off with minimal casualties simply by choosing to enter the wormhole closest to it, moving to its hub to maximize my fleet's angular velocity relative too the wrath lance, and staying ahead of the rotating lances while firing. Given the damage output of my fleet, it went down quickly and all it killed were a few stragglers that I didn't micromanage well enough.
I imagine that coupled with any guard post that seriously interferes with movement or targeting it could be truly brutal, but when the others were generic damagedealing types, not so much. It only had 60 million health, so once it was in range it died in seconds.
Again, this was on 7/7 and with a larger fleet than one would have by playing minimum AIP games, but at least on that difficulty it wasn't too bad.