This is an interesting (and very superficial) video interview with a few thriller writers about the difference between a thriller and a mystery. The writers each tend to define mystery as a traditional whodunit rather than a crime novel; although the lines between crime and thriller are heavily blurred. I tend to prefer modern crime and mystery novels to thrillers--modern thrillers tend to be too big and bombastic, and usually challenge my willful suspension of disbelief.
I do like the idea one of the authors had about mysteries (to paraphrase): they tend to be intellectually stimulating. He was speaking of the whodunit, but the major advantage of the crime novel is that it is a terrific vessel for social commentary, which is the element that draws me to it.