The breadth of the information. Zoom Info has contact details and info that I cannot find anywhere. I regularly impress friends, clients and colleagues with it's abilities.
It would be great to have some Canadian emails, but alas this is not possible given legislation.
Go for it! Expensive, but worth the cost if you are doing prospecting and outreach.
I have been able to quickly and directly get a hold of people I previously did not think possible, sales cycles have been shortened and outreach has become much easier.