Although i haven't tried the Armson Stealth, I'd have to say the J&J Ceramic is pretty damn good. Unfortuneately it dosen't do good for me all the time (see my Barrel Problems! post) but when it works its accurate and alot quiter than the stock barrel.
2k3 Blue Vert Autococker (Stock for now)
14" J&J Ceramic (modded),
Creating a ULE AutoMag