@eoe,
I understand that hesitation, eoe, so I did a little reading around.
Silicone is made from sand and oxygen so it appears to be safter than plastics and non-stick surfaces added to regular bakeware. According to what I read it is completely biodegradable -- there really aren't any "chemicals" used in it.
Although it has been on the market in other countries for years there have been no long term studies of possible health effects, so that is surely something to consider.
A few reports I read mentioned a funny smell (this seems to be associated mostly with Kitchen Aid brand) but I didn't notice any of that. The cupcakes I made smell and taste just as they should.
The only wacky thing I noticed is that the cupcakes rose off center; they're lopsided. Since I have to finish up my basic baking today I'm going to pay more attention to how they are placed in my oven to see if that perhaps is the reason.