A short disclaimer: I think Starsan is a great product. I'm in no way dissing it.
But I've had a particular problem with the foam. When transferring from fermenter to bottling bucket, it blocks my view of the tubing placement. I can't tell whether the tubing is lying on the bucket bottom or 3 inches over it. Because of this, I think I have aerated a couple of batches. It's hard to siphon quietly when you can't see what's going on.
So I'm staying with Starsan for sanitizing on brewday, but switching to Iodophor for bottling.
Has anyone else had this problem? Maybe I'm missing something.