Assistants, assholes? Wow.
This is a great attitude for a hiring manager to have; I am sure it helps you find the best of the best along with motivating your said "assholes" from giving you their undivided attention.
I plus one for having a few great assistants on my list. However, I will say that there is a learning curve that anyone needs to go through when working with some one new. Lets not forget that we have own style of lighting and staging that they need to learn first. This could take a few shoots and we need to give them that before making an assessment.
The biggest complaints I hear from my assistants is when they work for a photographer the first time and are expected to know exactly how they are going to light and stage the scene without being told. Second complaint, being blamed for the mistakes of the photographer. (IMHO, you should really know how to use your own damn camera, including troubleshooting, setting different modes, actually shooting the thing, how to properly tether the camera, knowing how to use your Raw or Viewing processors, etc.)