I also have been shopping for a "Fall-Away" rest, and found a pretty comprehensive article by Anthony Barnum which compares many of the top "Fall-Away" rests out there. It gets a bit technical but will show how the best tested in the important categories (noise, ease of set-up, etc...).
Worth a look anyway if you are considering purchasing a new rest.
http://www.archerytalk.com/archerytechevaluations/2006fallawayrests/DropAwayFaceOffReportAT.pdf