Microsoft

Very bright people, healthy, positive culture of collaboration and achievement.

Lots of experienced people around to learn from, ample room to grow.

Contractors get the short end of the stick and are often left out of company events. They always feel like second-class citizens for no good reason, and contractors constitute a lot of MS employees. Advancement options for contractors are often stunted, which means it can get difficult to maintain motivation over time.

If you want to maintain flexibility with parts of the workforce, rework it so that they still can fully feel part of the company. Maintain a bigger ratio of FTEs to contractors and rotate them more so that it's clear that becoming an FTE is a valid aspiration.