Two established scholars in New Testament studies taking each other to task.
Ehrman is doing what he does best: Pointing out "contradictions" in the four gospels as the reason to doubt the historical reliability of them, and hence the historical portrayals of Jesus. If these accounts contradict each other, then they are not historically accurate. Hence we cannot be too quick to assume their reliability.
Evans highlights the first principle that contemporary biblical scholars ground their researches (including that of Ehrman): The gospel accounts are reliable as far as historical research is concerned, and this is the starting point of biblical scholarship itself. Can we assume these documents are inaccurate just because we cannot make historical sense from them despite there are details found in them that correspond with archaeological findings and extra-biblical historical data?
Both agree that the gospel accounts are difficult for contemporary readers to comprehend. For Ehrman, this means "contradiction" and so we must read them as fabrication---those events just didn't happen.
For Evans, this means that we can still ascertain historical data from the texts even though there is difficulty---we have to continue to work on understanding those difficulties with what we can historically affirm.
Isn't the two scholars' so-called historical conclusion philosophical differences?