is amazon vine worth it for a brand new product listing?

Timing is the other thing. The reviews come in over a few weeks, not days, so I'd hold off on heavy ad spend until a few are up. Sending paid traffic to a zero review listing burns money. The reviews also carry a Vine label. Most shoppers don't care, just don't be surprised by it.

For a brand new listing with zero reviews it's one of the few legit ways to get some, so usually yes. You need Brand Registry and the product on FBA, and you give the units away free on top of the enrollment fee, so work out the real cost first. The catch: Vine reviewers are honest and fairly picky. If the product or the listing has a weak spot (sizing, packaging, instructions) they will say so in public. Fix anything you already suspect before you enroll, not after.