Rude, condescending, dismissive, and smug are all words I would use to describe Corestaff employees based on my interactions with them.
Even basic attempts to get registered, coordinate resumes, and provide other routine paperwork are met with ignorance, impatience, and smug arrogance. The woman named Laura is particularly rude. Why this agency is so willing to burn bridges professionally is beyond me!
As for the assignments, I've worked for this company three or four times at Amazon.com. Not all assignments were bad, but many were awful. Despite my proactive attempts to make my most recent assigment end on a positive note, was the worst.
Unfortunately and (inexplicably) this is the only agency that Amazon.com works with for temps, so if you want to work there, you're better off trying to find a full-time position through networking.
If you're desperate and have very low self-esteem, you'll probably be willing to put up with all of the unprofessional behavior to get a temp job. Otherwise, seek employment elsewhere. I've finally learned my lesson, and will be using a different agency.