It's not available in my area so I haven't tried it, but I would think the sugar free Callebaut would be your best bet. As far as taste goes, it'll be just as good as the real thing, as it's maltitol based. Maltitol in baked goods/confectionary is pretty much indistinguishible from sugar.
Maltitol does have it's downside, though. It can be laxating if consumed to excess. For some people it can be laxating, period. It's also pretty high GI (Glycemic Index). A small portion of the sugar free/low carb community avoids it. Most people reaching for sugar free desserts are not that aware. I do see this changing, though.
As far as sugar free chocolate that doesn't include maltitol or lactitol (also laxating), that gets tricky. Hershey used to make an erythritol based chocolate called 1 carb, but from what I believe, they stopped making it. If your interested in a non maltitol chocolate, I'll dig up some sources.
Otherwise, go with the maltitol. It's a carbon copy for sugar and available in bulk from Callebaut.
Btw, you need this just for enrobing, right? An excellent ganache can be made with unsweetened chocolate and artificial sweeteners.