Let's look at the pros first shall we?
- They mastered time - I cannot lie this is a major plus for them.
- They have advance tech at their disposal - in the story shadow out of time the narrator mentions a "lighting" gun.
- The ability to send their minds into the distant past or far future - they seem to do this either to gather knowledge or to flee a disaster.
- They imprisoned the flying polyps - yeah....only for a short period of time.
- They have the ability to possess the bodies of unsuspecting individuals from multiple time periods or planets. - this is impressive..but also a dick move.
Now for the cons -
- The forms they choose to inhabit when they escape destruction. They choose a half vegetable conical form instead of something like a trex..then they flee into the future and take over a race of beetle like creatures.. why didn't they look for something more imposing? Because they are lazy and settle for anything...
- For all of their intelligence and wisdom why didn't they foresee the destruction of yith? The answer is simple... they lacked common sense or they were to busy to notice..
- They built their home over the spot they imprisoned the flying polyps - again this shows lack of any sense at all.
- They dont like coffee - enuff said
So based on these pros & cons I say they are really average.