Regarding blasting, the primary difference would be volume. What you could blast with a box store blaster in an hour, we could do in a minute. That is if you had the pressure. There are many situations where a box blaster wouldn’t be able to make a dent on what is being removed. With our blaster we have enough pressure to blast extremely hard concrete, 60+ mpa, which a box store blaster would only blow the dust off of.
Regarding a pressure washer, the primary differences are 1) we can control our pressure for different types of substrates and 2) we create a profile for adhesion. A normal pressure washer will only remove dirt or loose material. It will not create any profile for adhesion.