Vanillin acetate is, of course, less powerful than vanillin (the aldehyde). However, what it loses in raw strength it makes up for in other ways. For example: it's less cloying, powdery, and choking than vanillin or ethyl vanillin.

Instead of these qualities, it has a certain finesse and brightness (Arctander Agrees) which is unusual for the typical vanilla materials. If you know Isobutavan, you'll know that this isobutyrate ester is fruity, almost towards white chocolate and yoghurt.
 
By contrast this rarely offered vanillin acetate (also known as Acetyl Vanillin) doesn't go full fruit; instead, it hovers just beyond vanillin in terms of "true vanilla" character but adds this aforementioned crystalline quality. It's also more forgiving when dosing, and allows you to augment hypergourmands beyond the ~5% vanillin dose at which adding extra vanillin seems to confer no additional benefit :)