The notion of a "missing link" is BS, but talk of transitional fossils is legitimate, only if one knows what one is talking about, which most creationists don't. They want us to show them fossils at one moment in time that were a cross between one thing and another, but that's not the way evolution works. It works in stages, and transitional stages are well documented in the fossil record. So creationists are not bringing any challenge worth answering. So, yes, their notion of transitional fossils is BS. Also, a better term is intermediates. None is at THE transition point because there is no transition point. No two parents ever gave birth to a transition between two species. And there was no first specimen of any species. Species, genera, families, etc, are just names we use to help organize fossils, not reality. The reality is that every fossil we find is an intermediate linking what came before to what came after. Every fossil of early man we've found is an intermediate linking modern humans to the common ancestor we share with chimps. Evolution is one long exercise in intermediacy, and even we are an intermediate form.