That's from personal experience, but of course YMMV, but I've often found myself in the situation where it's late in the evening, things are not working right in the production environment and the only people left at the office are the consultants.

(Responding way late :)

That is because consultants are getting paid by the hour and are often not in their home town so their option is 1) get paid more or 2) go to the hotel alone and watch TV. I always chose option 1 if I could.

In a company with vested employees who believe in the company, there will be no comparison between the employees and consultants in their dedication and professionalism.