If it is the same thing as rice solids, I've used them as a barley malt substitute a few times, for the same reason that the big commercial brewers use it - to get a lighter flavor and color in my beer. I use them for fruit beers along with a light hops load so that the fruit flavor and color is not drowned out.
I have not used them as priming sugar substitute (as one might infer from the original question). I don't think they would be suitable for this - in my experience they do not produce a nice tight, compact sediment layer; the left-overs tend to stay suspended. This can be managed by an extended stay in a secondary or tertiary stage but I think that the normal bottle setting would leave too much cloudiness, and the sediment would be too easily stirred up (for my tastes anyway).