Hello Phil,
It really comes down to quality and price (plus figure in speed, too). If you want to go with a software solution that you can install on the Avid workstation, check out Procoder from Canopus. It’s eclipsed Cleaner in a handful of ways, and is a “cleaner” encoding engine than Sorenson Squeeze, in my opinion.
Hardware encoders can produce fabulous results and have a definite speed advantage, but I wouldn’t install the hardware on an Avid system. Buy a cheap, basic, but fast PC for it. Export an uncompressed QT file for best quality to a external drive, start it up, and put a kettle on.
Valerie