Hey there, I can't quantify what impact these links have had on my map pack rank as I've been doing a lot of different things in the last two months to step up my GMB and my SEO game in general, including a local citation package (which IMO is a more important factor when it comes to ranking your GMB). I don't expect these links to jettison me to the top 3 of map pack in a large metropolitan area.
With that being said, I was in the market for some web 2.0 links anyway, and this service was still fairly priced, so I decided to purchase a package. I wasn't disappointed with this purchase, but I keep my expectations grounded at this price point.
EDIT: also, keep in mind that I bought this package like 3 days before the may google update. Even if my rank had shot up or down (and it did), there's a quadrillion factors to account for here.