Vantaggi
This is an agency that understands that the contractors are not lightbulbs, we are people. The recruiters not only spend extra time making sure there's a good fit with the client but that their contractors are happy, doing well, meeting the clients' needs, and not being abused.
I was one of a number of people working for a very difficult client in Beaverton and the agency spent a lot of extra time making sure we were all surviving and not getting beat up too badly. I actually rather enjoyed the client, but I can't say that I miss the client now that I'm gone.
If you have a chance, work with Lynn Soland, who is one of the top three recruiters in the Greater Portland area. Many technical communicators and IT people have been her devoted fans for 15 years. She goes the extra mile for her people and we love her for it. But everyone at the ieSolutions office in Beaverton I've talked to has been friendly, motivated, and fun.
Svantaggi
There are not more agencies as good as ieSolutions. :)