I worked a contract for IASCO from 10/99-07/00 and would do it again in a heartbeat.
This was a domestic contract flying cargo on a 727, but the support was there and the pay always on time.
The operator we were contracted to tended to look the other way and cut a few corners here and there when it came to MEL items and FAR 121 duty and rest times. Although their pilots seemed to be ok with this, a quick call to IASCO soon sorted it out for us "contract" guys.
Louise Philips was our contact at IASCO, and in my experience, everything she said was straight and honest, and all of my expectations were met.
I would highly recommend IASCO as a reliable contractor.