Product review (5 stars): This is the one to get!
As previously mentioned, this item is much less expensive via Amazon than it is from some of the big parts houses.  It fit perfectly, and has metal threads instead of the plastic threads on the original.  One thing to note is that this knob originally came in a few colors, but the manufacturer dropped all those and this replacement is simply black (with the shiny disk in the middle as pictured).  Even if you pay 30 or more dollars for this part, I think you'll get a black one.