Its generally agreed by people who have used both that the Stealth is quiter than the RA's but that there is no difference in power or accuracy. The trigger mech is supposedly toughened up but since it also uses the euro style "pinch action" sear its probably not worth the risk loading 2 20mm rubbers on it.
Dogmatrix bought one recently as did a few of the guys on the Adrenaline forum (
www.spearfishing.com.au), I have an RA myself and am very happy with that!