I just looked into this for someone that was recently diagnosed diabetic (as well as for me). From what I can tell it's less dangerous than something like aspartame. I think it's made by chlorinating sugar, and it seems to be less dangerous than something like aspartame. Pre-approval tests showed it caused liver and kidney problems in lab animals but they explained that away somehow, don't remember how exactly. I think I also read about a study that showed it caused bladder tumors in rats but that might have been a different artificial sweetener. The story is the same as all the other artificial sweeteners though, they do enough tests to get it approved as being safe and then the studies stop and no one collects any data from the humans that could be guineau pigs. It should be fairly obvious that the reason for the info blackout after the approval is to make sure no one questions it's safety, but who knows if it's safe, now that it's approved industry is working to make sure that question doesn't get asked much less answered.
Personally I wouldn't use it, I recommended to this diabetic that they use sucralose with other sweeteners to spread their risk around. It all comes down to how much risk are you OK with... you see non-stick frying pans everywhere and no one is concerned they give off toxic gases... I'm sure it's the same with sucralose. Maybe increase your risk of cancer by 3% over 60 years of use... who cares?