I was on the TPK end of a campaign that (at the end) had one of its gods go insane. All of his angels were still LG, but following his order to kill all things Neutral and evil, so they were cutting a path of destruction through the world.

The problem is that Angels (Solars in particular) are not made to be an enemy. They have stupid op powers like ____ at will, and heal every round, and other crazy stuff no other creature has.

So use them sparingly as enemies. You'll have to nerf them, play them dumb, or have TPK.