Sagent, MSN, On Assignment & Millenia have very good reputations & pay decently.
Sagent is particulary known for it's superb housing and health insurance.
MSN for its pay and customer (nurse) service.
On Assignment for it's housing and rental car option, while maintaining a decent pay rate.
Millenia for it's pay rate, good housing and honest recruiters.
Have also heard good things about ADEX; but, have no actual experience with them except to discuss the possiblity of a few assignments-however, the recruiter was honest and not pushy and the pay was well above average (he just didn't have an assignment in the area I was looking for at the time).
AM is part of what is referred in the travel nurse world as "the evil empire"
Heard that Nightengale Nurses does not back it's employees up when it comes to patient safety issues.
You might find it benefical to look at a site:
www.pantravelers.org
And, a word of advise----don't judge the recruiter on how nice they are to you and how well you bond with them. It is OK to be friendly, but always maintain a distance and business relationship, or you may find youself being taken advantage of and not even knowing it.