First page is nice but there is big gap between #1,#2, #3 spots on first page vs. rest of that page. From what I've seen #1,#2,#3 have large majority of views, the rest get the crumbs in a rapidly declining curve. And after the first page, percentage-wise it's in the low single digits for ALL those sad people in the long tail, combined! Unable to determine what you mean by massive impact, since its unknown what the global/local keyword search volume is in total. In summary: if they got you to #1,2,or MAYBE 3 on first page, that's decent. If not, it's a wash. Or it might just take a while, who knows?