(1.) When I checked out the suggested non-canonical sources for some of the Markan miracle stories I found that the parallels were weaker than suggested by Price. (2.) His analysis also fails to establish whether parallels between Mark and other sources indicates dependence. (3.) The story or narrative element of the Gospel is unnecessarily downplayed.
This is a very good introduction to the gospels. The emphasis is on interpreting the gospels in their own terms as literary and theological works. Historical issues are dealt with in a constructive manner.