graeme_p ask for a three month introductory contract. That's what I was eventually offered. When the three months are up I'll consider what to do. At this point it's no-brainer though, earnings are better than even their estimate.
In the end though, how are Vibrant ever going to enforce the 12 month contract if you are not happy? They understand that, they just want some confidence in your level of commitment at the beginning.