Err, comments on Spirent

It sounds like you like the Spirent offer more. But it won't cut it if Spirent just uses an temp agency as the temp agency can not do H1 for you. What you need is a consulting company which does service instead of just headhunting.

On another note, I am not sure why Spirent would go through so much trouble (outside agency, more $) to avoid to hire you full-time and do H1. Hiring freeze is not a good reason as the company is spending more $ by let you stay as temp. The only reason is that they do not see long term need for you, or another word, they can let you go in 3-6 month.