Interesting... I think that ill-defined meaning of the word of evolution contributes to the confusion. Natural selection as a selective breeder is an established scientific principle. The effects of mutations are easily observable as well [often destructive or harmful]. However, translating those concepts into historical reconstruction from common descent is faith in the improbable.
Or its simply a description of the fossil record. We've played the "what is it" game on crevo threads dozens of times.
Even in their own literature, creationists are all over the map when it comes to identifying members of the human family. Some say the australopithicines are human, some say they're not.
The argument for evolutionary biology really rests on the fossil record. While the genomic record continues its growth, it has overwhelmingly supported the morphological relations already identified, but its barely started. So it's hard to say much more than, so far so good.
A single billion-year mammal fossil would create enormous problems for evolution as a theory, but so far, none have been found.