I could start with the CBSA.
It varies. Detector dogs are a different type of tool. You have a human coupled with a dog. That's an asset as well. The dog sleeps. The dog eats. Machines don't. But the machines on the other hand do go down. They need maintenance and such. Trying to compare that piece is apples and oranges.
In addition, there is X-ray technology, which is also helpful, and about the same price range, depending on the type of X-ray technology you get, but it's a different tool to do something different.
An X-ray will tell you if something is concealed within, let's say, baggage or parcels. The ion scan will tell you if there's a residue of something. The detector dog will tell you if there's an odour of some type of concealed narcotic.